Title of Invention	"AN IMPROVED PROCESS FOR PREPARING BULK MONOLITH OF CARBON SUB SIXTY FULLERENE-GLASS COMPOSITE, USEFUL IN DEVICE APPLICATIONS AS NONLINEAR OPTICAL MEDIUM AND OPTICAL LIMITER"
Abstract	The present invention provides an improved process for preparing bulk monolith of Carbon sub sixty fullerene-glass composite useful in device applications as nonlinear optical medium and optical limiter by heat treating a weather resistant glass composition at a temperature ranging 400-900° C to obtain a solid mass , crushing the solid mass into granules/powder , adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% , heat treating the mixture at a temperature ranging 350 -390 ° C under vacuum , melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere . The melted mixture resulted into transparent monolithic glass after proper cooling.

Title of Invention

"AN IMPROVED PROCESS FOR PREPARING BULK MONOLITH OF CARBON SUB SIXTY FULLERENE-GLASS COMPOSITE, USEFUL IN DEVICE APPLICATIONS AS NONLINEAR OPTICAL MEDIUM AND OPTICAL LIMITER"

Abstract

The present invention provides an improved process for preparing bulk monolith of Carbon sub sixty fullerene-glass composite useful in device applications as nonlinear optical medium and optical limiter by heat treating a weather resistant glass composition at a temperature ranging 400-900° C to obtain a solid mass , crushing the solid mass into granules/powder , adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% , heat treating the mixture at a temperature ranging 350 -390 ° C under vacuum , melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere . The melted mixture resulted into transparent monolithic glass after proper cooling.

Full Text	The present invention relates to a novel process for preparing bulk monolith of Carbon sub sixty fullerene(C6o)-glassf composite useful in device applications as nonlinear optical medium and optical limiter Fullerenes are a class of recently discovered closed shell carbon molecules having ditlerent optical and opto-electronic properties. Amongst the various homologues of the series which may consist of carbon atoms ranging in number 'from 20 to 980 and even more (Science of Fullerene and carbon nanotudes - M.S. Dresselhaus et al, Academic Press, 1996), the most stable and widely investigated molecules are carbon sub sixty and carbon sub seventy fullerenes. Structurally, C. sub sixty & C. sub seventy have similarity in the sense, they are similar to those of linear quasi-one-dimensional conducting polymers, such as poly-acetylene. This is due to the presence of extended network of conjugated delocalized pi-electrons which are distributed over the spherical fullerene surface. These new compounds have a wide variety of remarkable properties. As in the case with many conjugated polymers, the electrical conductivity of C. sub sixty & C. sub seventy can be varied to make them insulators, semi conducting and even super conducting by controlled n-type doping. Tutt & Kost (US Patent No.5, 172, 278 dated Dec 15, 1992 ) have first shown that both C. sub sixty and C. sub seventy fullerene solutions can be used as an optical limiter, transparent to low intensity light but nearly opaque above a critical intensity. It has been shown further, (N. S. Sariciftci, A. J. Heeger, in US Patent No.533183) that fullerenes C. sub sixty and C. sub seventy may be made technologically useful as photoconducting film by incorporating them into suitable organic conducting polymer. However, one of the major difficulties in using fullerenes for all such applications is that they are unstable under ambient environmental condition. Oxygen and water in presence of light are known to react with fullerenes. It is therefore, necessary to encase these materials in an inert host while fabrication of a device using fullerene is considered. Thus incorporation of fullerenes in suitable glass matrix should be of immense benefit as far as various applications like optical limiter and non linear optical medium, photoconductor are concerned. Lui a drawback of use of fullerene-organic polymer composite film is that fullerene is not fully protected from environmental degradation. , Many workers all over the world therefore, tried to develop C. sub sixty and C. sub seventy fullerene-glass composites. There are number of reports of experiment on encasing fullerene C. sub sixty and C. sub seventy in glassy hosts with limited success. In most these cases, however, fullerene was tried to encase in silica host by sol-gel methods, e.g. methods described by R. B. Mattes et al in US Patent No. 5,420,081 dated May 30, 1995 and by Sheng Dai et al in J. of Am Cer. Soc. 75 (1992) 2865. In all these cases, preparation of thin films of dimensions not larger than 13-15 mm x 0.5 mm having clusters of C. Sub sixty fullerene distributed in the host were reported. In some cases, certain derivatives of fullerene have been used to prepare thin plate of silica-C. sub sixty fullerene composite by sol gel method for application as optical limiter (R. Signorini et al SPIE vol. 2854, page 130). In all these cases, C. sub sixty fullerene is not totally protected from the environmental degradation by the water associated with the hosts. F. Lin et al reported [Appl. Phys. Lett. 65 (1994) 2522] preparation of C. sub sixty fullerene doped phosphate glass by melting in a sealed device. S. Mao et al Chinese Patent No. 93112519.7, (1993)] The main drawbacks of the existing methods are as follows: 1) Drawback of the sol-gel method is that Fullerenes are not totally protected from environmental degradation in the resulting composites. 2) The drawback of the Chinese method is that they used a methud of melting in a sealed device to prevent oxidation and escape of fullerene at high temperature; hence the method is not suitable for commercial exploitation for preparing bulk monolith. The object of the present invention is to provide a process for preparing bulk monolith of carbon sub sixty fullerene-glass composite useful in device applications as nonlinear optical medium and optical limiter. Another object of the present invention is to provide a process for preparing C. sub sixty fullerene - glass composite having C. sub sixty fullerene homogeneously dispersed in the host. Yet another object of the present invention is to provide a process for preparing bulk monolith of the C. sub sixty fullerene - glass composite in the size of relatively large dimensions suitable for different device applications. Another object of the present invention is to provide a method for preparing bulk monolith of C. sub sixty fullerene-glass composite which can effectively prevent oxidation and escape of fullerene with the increase of temperature and at the same time simple and versatile for commercial exploitation. Accordingly the present invention provides an improved process for preparing transparent monolithic glass of carbon sub sixty fullerene - glass composite , said process characterized in that heating at a temperature range of 400-900° C a weather resistant glass composition , having melting point below 800 ° C to obtain a solid mass , crushing the solid mass into granules/powder , adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% , mixing the two intimately , heat treating the mixture in a carbon crucible at a temperature ranging 350 -390 ° C under vacuum , melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere as described herein , cooling the melt to get desired transparent monolithic glass. In an embodiment of the present invention the glass composition used may be such as 0-50 mole% of phosphorous pentoxide (P205), 0-40 mole% of boron oxide (B203) , 0-30 mole% of bismuth oxide (Bi203), 0-1 mole% of silicon dioxide (Si02), 0-1 mole% of aluminium oxide (AI2O3), 10-45.5 mole% of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole % of tin dioxide (Sn02), adding to the mixture 0-5 mole % M20 where M = Na, K, Li. In another embodiment of the present invention the phosphorous pentoxide used may be taken either as it is or in the form of compounds such as ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphoric acid. In another embodiment of the present invention the boron oxide used may be taken as compounds such as boric acid, sodium metaborate. In another embodiment of the present invention the lead oxide used is taken form lead carbonate, red lead. In another embodiment of the present invention the bismuth oxide used may be either as it is or substituted by compounds selected from bismuth nitrate, bismuth chloride, bismuth hydroxide. In yet another embodiment of the present invention the alkali metal oxide ( M20 , M= Na, K, Li) used may be taken in the form of respective carbonates. In another embodiment of the present invention the inert gases used may be Helium, Nitrogen, Argon , or a mixture thereof. Brief description to drawing : Curve showing optical absorption study of carbon sub sixty fullerene - glass composite. Y axis indicates intensity of band at a particular frequency of electromagnetic radiation as indicated by x-axis. Unit of Y-axis is arbitrary as abbreviated "abs". The single peak at frequency 625nm indicates the presence of C. sub sixty fullerene in the entire matrix . Any heterogeneity would have resulted into more number of peaks. The detailed process steps of the present invention are: 1. Heating at a temperature in the range 400-900 ° C a glass composition of 0-50 mole% of phosphorous pentoxide , 0-40mole% of boron oxide , 0-30 mole% of bismuth oxide (Bi203), 0-1 mole % silicon dioxide (Si02), 0-1 mole % of aluminium oxide (AI203), 10-45.5 mole % of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole% of tin dioxide (Sn02) 2. Adding to the mixture 0-5 mole % alkali metal oxide (IM2O where M = Na, K, Li) 3. Adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% 4. Mixing the two components intimately 5. heat treating the mixture in a carbon crucible at a temperature ranging 350 -390 ° C under vacuum 6. Melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere 7. Cooling the melt to transparent monolithic glass. Novelty of the present invention lies in providing a process for preparing bulk monolith of C. sub sixty fullerene -glass composite which is effective in homogeneous incorporation of fullerene without environmental degradation and is suitable for commercial exploitation. The above novel feature has been obtained through the following inventive steps: 1. Use of two step method of melting to avoid environmental degradation of C. sub sixty fullerene at the time incorporation of the latter in the glass. 2. use of technique of 'heat treating under vacuum then melting under inert atmosphere in a furnace that can accommodate a batch ranging from small to moderate size'. The following examples provided below are by way of illustrations only and should not be construed to limit the scope of the invention. EXAMPLE -1 About 70 gms of the glass was prepared by making an intimate mixture of 0.30 mole of P2O5, 0.25 mole of PbO, 0.006 mole of AI2O3, 0.006 mole of SnO2 and 0.045 mole of ZnO - sintering the batch mixture in an alumina crucible in a furnace at 500°C to a fused mass - crushing the mass into powder - adding 6.0 mg of C. sub sixty fullerene to the powder - heat treating the mixture in a carbon crucible around 360°C for 3 hrs under vacuum - finally melting the mixture at a temperature around 680°C for 35 minutes under controlled atmosphere of nitrogen gas. The glass obtained was a monolithic sample having C. sub sixty fullerene dispersed in the form of small clusters. Example - 2 The fullerene containing glass in an amount 35 gm was also prepared by using mixture of ingredients like 0.16 mole of B2C3, 0.035 mole SiO2, 0.02 mole of AI2O3 and .015 mole of PbO - melting the batch in a platinum crucible in a furnace at around 650°C - cooling the molten mass in the form of lump crushing the same into powder - adding 3 mg C. sub sixty fullerene to this host material - heat treating the mixture in a carbon crucible at 380°C for 2 hour under vacuum - then melting the mixture at 750°C for 20 mins to a vitreous liquid under controlled atmosphere of nitrogen. The glass obtained showed a pink tint. Example - 3 In an another trial, 80 gm of the glaiss was prepared by using a batch mixture ofO.06 mole of ZnO, 0.25 mole of PbO - reacting the mixture with 0.3 mole of P2O5 - sintering th reaction product in an alumina crucible to a consolidated mass at a temperature around 600C in a furnace - crushing the lump into granules - adding 8 mg of C. sub sixty fullerence to the latter - heat treating the fullerene containing mixture in a carbon crucible at around 370°C for 1 hrs under vacuum - finally melting the mixture to a vitreous melt around 660°C for 0.5 hr under controlled atmosphere of helium gas. The glass obtained was monolithic sample with homogeneous dispersion of C. Sub sixty fullerene. Example - 4 Another sample of the glass weighing around 60 gms was prepared by using a mixture of ingredients like 0.27 mole PaOs and 0.27 mole of ZnO - adding 0.06 mole of PbO - sintering the mixture in an alumina crucible at 550°C in a furnace to a solid mass - crushing the product into powder - adding 6 mg of C. Sub sixty fullerene to a resulting powder - mixing them intimately in a vibrator - heat treating the same around 380°C in a graphite crucible under vacuum for one and half hour - finally melting the mass at 770°C for 25 minutes under controlled atmosphere of helium gas. The glass sample obtained had a light pink tint with particulate dispersion of C. Sixty fullerene. Example - 5 About 35 gm of another glass was prepared by using a batch mixture consisting of ingredients like 0.15 mole B2O3, 0.06 mole of PbO, 0.06 mol of PbF2 and 0.03 mole of ZnO - melting the batch ina platinum crucible to a sintered mass at a temperature around 700°C - converting the mass in the form of granules - adding 3 mg of C. Sub sixty fullerene to the former -mixing the components intimately - heat treating the mixture in graphite crucible at around 370°C for 1 hr under vacuum - then melting the mixture by increasing the temperature up to 725°C for 20 mins. The glass obtained showed a faint pink tint. Example - 6 C. sub sixty fullerene containing glass was also prepared in a quantity of 50 gms by using a batch mixture of 0.023 mole of AI2O3, 0.3 mole of ZnO, 0.03 mole of PbO and 0.01 mole of Na2O -reacting the mixture with 0.30 mole of P2O5 - sintering the reaction product to a consolidated mass at a temperature around 550°C - cooling the sintered mass to room temperature - crushing the same into granules - adding 5.0 mg of C. sub sixty fullerene to the host granules - mixing the same in a vibrator - heat treating the resultant mixture in a graphite crucible around 380°C for 11/2 hrs under vacuum - finally melting the same at around 880°C for 30 mins under controlled atmosphere of mixture nitrogen and argon gases to form glass. The glass obtained was a monolithic sample of 20 mm thick. Example - 7 40 gms of similar glass was also prepared by using a batch mixture of 0.12 mole of PbO, 0.14 mole of B6O3 and 0.045 mole of SiO2 - heat treating the mixture in an alumina crucible at around 550°C for 5 hour to transform into a sintered mass - crushing the product into powder - adding 3 mg of C. sub sixty fullerene to the powdered host - mixing the two components intimately -heat treating the mixture in a carbon crucible at around 390°C for 1 hr under vacuum - finally melting the same by raising the temperature to 730°C for 30 mins under controlled atmosphere of argon to form glass with homogeneous dispersion of C. sub sixty fullerene. A light pink coloured glass was obtained. Example - 8 35 gms of such glass was also prepared by making a batch mixture of 0.03 mole of ZnO, 0.12 mole of PbO and 0.15 mole of B2O3 - melting the batch in a an alumina crucible at around 700°C to glassy mass - crushing the glassy mass into pieces - adding 3 mg of C. sub sixty fullerene to the former - heat treating the new mixture in a carbon crucible at around 380°C for 1 hr in a closed furnace under vacuum - finally melting the material at about 750°C for 20 mins under a constant flow of nitrogen. The melt was cooled - the glass obtained did show purple tint. Transparent monolithic samples of C. sub sixty fullerene - glass composite prepared in different size and shapes using varied glass compositions and with different concentrations of the C. Sub sixty fullerene as described above, showed the existence of homogeneously dispersed C. sub sixty fullerene in the glass both as isolated molecules and small clusters, as have been revealed by optical absorption study as shown in Fig. 1 of the drawing accompanying the specification. The single peak at frequency 625nm indicates the presence of C. sub sixty fullerene in the entire matrix . Any heterogeneity would have resulted into more number of peaks. The main advantages of the invention are: The present method for preparing C. sub sixty fullerene-glass composite can be used to prepare bulk monolith useful in actual device applications. 1. It is superior to sol-gel process both in respect of homogeneous dispersion and protection of C. sub sixty fullerene from environmental degradation. 2. The method is simple and cost effective. We Claim : 1. An improved process for preparing transparent monolithic glass of carbon sub sixty fullerene - glass composite , said process characterized in that heating at a temperature range of 400-900° C a weather resistant glass composition such as herein described , having melting point below 800 ° C to obtain a solid mass , crushing the solid mass into granules/powder, adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% , mixing the two intimately , heat treating the mixture in a carbon crucible at a temperature ranging 350 -390 ° C under vacuum , melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere as described herein , cooling the melt to get desired transparent monolithic glass. 2. An improved process as claimed in claim 1 wherein a glass composition used is 0-50 mole% of phosphorous pentoxide (P2O5), 0-40 mole % of boron oxide (B2O3), 0-30 mole % of bismuth oxide (Bi2O3), 0-1 mole % silicon dioxide (SiO2), 0-1 mole % of aluminium oxide (AI2O3), 10-45.5 mole % of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole% of tin dioxide (SnO2), adding to the mixture 0-5 mole % alkali metal oxide (M2O where M = Na, K, Li). 3. An improved process as claimed in claims 1- 2 wherein phosphorous pentoxide (P2Os) used is either as it is or from compounds selected from ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphoric acid. 4. An improved process as claimed in claims 1 - 3 wherein boron oxide (B2O3) used is selected from compounds boric acid, sodium metaborate. 5. An improved process as claimed in claims 1-4 wherein lead oxide (PbO) used is selected form Lead carbonate, red lead. 6. An improved process as claimed in claims 1-5 wherein the bismuth oxide (Bi2O3) used is either as it is or as compounds selected from bismuth nitrate, bismuth chloride, bismuth hydroxide. 7. An improved process as claimed in claims 1-6 wherein alkali metal oxide IvbO (M=Na, K, Li) used is in the form of respective carbonates. 8. An improved process as claimed in claims 1 - 7 wherein the inert gas used is chosen from Argon, Nitrogen, Helium, a mixture thereof.

Full Text

The present invention relates to a novel process for preparing bulk monolith of Carbon sub sixty fullerene(C6o)-glassf composite useful in device applications as nonlinear optical medium and optical limiter
Fullerenes are a class of recently discovered closed shell carbon molecules having ditlerent optical and opto-electronic properties. Amongst the various homologues of the series which may consist of carbon atoms ranging in number 'from 20 to 980 and even more (Science of Fullerene and carbon nanotudes - M.S. Dresselhaus et al, Academic Press, 1996), the most stable and widely investigated molecules are carbon sub sixty and carbon sub seventy fullerenes. Structurally, C. sub sixty & C. sub seventy have similarity in the sense, they are similar to those of linear quasi-one-dimensional conducting polymers, such as poly-acetylene. This is due to the presence of extended network of conjugated delocalized pi-electrons which are distributed over the spherical fullerene surface. These new compounds have a wide variety of remarkable properties. As in the case with many conjugated polymers, the electrical conductivity of C. sub sixty & C. sub seventy can be varied to make them insulators, semi conducting and even super conducting by controlled n-type doping.
Tutt & Kost (US Patent No.5, 172, 278 dated Dec 15, 1992 ) have first shown that both C.
sub sixty and C. sub seventy fullerene solutions can be used as an optical limiter, transparent to low intensity light but nearly opaque above a critical intensity. It has been shown further, (N. S. Sariciftci, A. J. Heeger, in US Patent No.533183) that fullerenes C. sub sixty and C. sub seventy may be made technologically useful as photoconducting film by incorporating them into suitable organic conducting polymer. However, one of the major difficulties in using fullerenes for all such applications is that they are unstable under ambient environmental condition. Oxygen and water in presence of light are known to react with fullerenes. It is therefore, necessary to encase these materials in an inert host while fabrication of a device using fullerene is considered. Thus incorporation of fullerenes in suitable glass matrix should be of immense benefit as far as various applications like optical limiter and non linear optical medium, photoconductor are concerned. Lui a drawback of use of fullerene-organic polymer composite film is that fullerene is not fully protected from environmental degradation.

, Many workers all over the world therefore, tried to develop C. sub sixty and C. sub seventy fullerene-glass composites. There are number of reports of experiment on encasing fullerene C. sub sixty and C. sub seventy in glassy hosts with limited success. In most these cases, however, fullerene was tried to encase in silica host by sol-gel methods, e.g. methods described by R. B. Mattes et al in US Patent No. 5,420,081 dated May 30, 1995 and by Sheng Dai et al in J. of Am Cer. Soc. 75 (1992) 2865. In all these cases, preparation of thin films of dimensions not larger than 13-15 mm x 0.5 mm having clusters of C. Sub sixty fullerene distributed in the host were reported. In some cases, certain derivatives of fullerene have been used to prepare thin plate of silica-C. sub sixty fullerene composite by sol gel method for application as optical limiter (R. Signorini et al SPIE vol. 2854, page 130). In all these cases, C. sub sixty fullerene is not totally protected from the environmental degradation by the water associated with the hosts. F. Lin et al reported [Appl. Phys. Lett. 65 (1994) 2522] preparation of C. sub sixty fullerene doped phosphate glass by melting in a sealed device. S. Mao et al Chinese Patent No. 93112519.7, (1993)] The main drawbacks of the existing methods are as follows:
1) Drawback of the sol-gel method is that Fullerenes are not totally protected from
environmental degradation in the resulting composites.
2) The drawback of the Chinese method is that they used a methud of melting in a sealed device
to prevent oxidation and escape of fullerene at high temperature; hence the method is not
suitable for commercial exploitation for preparing bulk monolith.
The object of the present invention is to provide a process for preparing bulk monolith of carbon sub sixty fullerene-glass composite useful in device applications as nonlinear optical medium and optical limiter.
Another object of the present invention is to provide a process for preparing C. sub sixty fullerene - glass composite having C. sub sixty fullerene homogeneously dispersed in the host.
Yet another object of the present invention is to provide a process for preparing bulk monolith of the C. sub sixty fullerene - glass composite in the size of relatively large dimensions suitable for different device applications.
Another object of the present invention is to provide a method for preparing bulk monolith of C. sub sixty fullerene-glass composite which can effectively prevent oxidation and escape of fullerene with the increase of temperature and at the same time simple and versatile for commercial exploitation.
Accordingly the present invention provides an improved process for preparing transparent monolithic glass of carbon sub sixty fullerene - glass composite , said process characterized in that heating at a temperature range of 400-900° C a weather resistant glass composition , having melting point below 800 ° C to obtain a solid mass , crushing the solid mass into granules/powder , adding carbon sub sixty fullerene to the granules/powder in the range of 0.05-0.1 overall wt% , mixing the two intimately , heat treating the mixture in a carbon crucible at a temperature ranging 350 -390 ° C under vacuum , melting the mixture at a temperature in the range of 600-800° C under inert gas atmosphere as described herein , cooling the melt to get desired transparent monolithic glass. In an embodiment of the present invention the glass composition used may be such as 0-50 mole% of phosphorous pentoxide (P205), 0-40 mole% of boron oxide (B203) , 0-30 mole% of bismuth oxide (Bi203), 0-1 mole% of silicon dioxide (Si02), 0-1 mole% of aluminium oxide (AI2O3), 10-45.5 mole% of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole % of tin dioxide (Sn02), adding to the mixture 0-5 mole % M20 where M = Na, K, Li.

In another embodiment of the present invention the phosphorous pentoxide used may be
taken either as it is or in the form of compounds such as ammonium dihydrogen
phosphate, diammonium hydrogen phosphate, phosphoric acid.
In another embodiment of the present invention the boron oxide used may be taken as
compounds such as boric acid, sodium metaborate.
In another embodiment of the present invention the lead oxide used is taken form lead
carbonate, red lead.
In another embodiment of the present invention the bismuth oxide used may be either as
it is or substituted by compounds selected from bismuth nitrate, bismuth chloride, bismuth
hydroxide.
In yet another embodiment of the present invention the alkali metal oxide ( M20 , M= Na,
K, Li) used may be taken in the form of respective carbonates. In another embodiment of the present invention the inert gases used may be Helium,
Nitrogen, Argon , or a mixture thereof.
Brief description to drawing : Curve showing optical absorption study of carbon sub
sixty fullerene - glass composite. Y axis indicates intensity of band at a
particular frequency of electromagnetic radiation as indicated by x-axis. Unit
of Y-axis is arbitrary as abbreviated "abs". The single peak at frequency
625nm indicates the presence of C. sub sixty fullerene in the entire matrix .
Any heterogeneity would have resulted into more number of peaks.
The detailed process steps of the present invention are:
1. Heating at a temperature in the range 400-900 ° C a glass composition of 0-50 mole% of phosphorous pentoxide , 0-40mole% of boron oxide , 0-30 mole% of bismuth oxide (Bi203), 0-1 mole % silicon dioxide (Si02), 0-1 mole %

of aluminium oxide (AI203), 10-45.5 mole % of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole% of tin dioxide (Sn02)
2. Adding to the mixture 0-5 mole % alkali metal oxide (IM2O where M = Na,
K, Li)
3. Adding carbon sub sixty fullerene to the granules/powder in the range of
0.05-0.1 overall wt%
4. Mixing the two components intimately
5. heat treating the mixture in a carbon crucible at a temperature ranging
350 -390 ° C under vacuum
6. Melting the mixture at a temperature in the range of 600-800° C under
inert gas atmosphere
7. Cooling the melt to transparent monolithic glass.
Novelty of the present invention lies in providing a process for preparing bulk
monolith of C. sub sixty fullerene -glass composite which is effective in
homogeneous incorporation of fullerene without environmental degradation
and is suitable for commercial exploitation.
The above novel feature has been obtained through the following inventive
steps:
1. Use of two step method of melting to avoid environmental degradation
of C. sub sixty fullerene at the time incorporation of the latter in the
glass.
2. use of technique of 'heat treating under vacuum then melting under
inert atmosphere in a furnace that can accommodate a batch ranging
from small to moderate size'.
The following examples provided below are by way of illustrations only and should not be construed to limit the scope of the invention. EXAMPLE -1
About 70 gms of the glass was prepared by making an intimate mixture of 0.30 mole of P2O5, 0.25 mole of PbO, 0.006 mole of AI2O3, 0.006 mole of SnO2 and 0.045 mole of ZnO - sintering the batch mixture in an alumina crucible in a furnace at 500°C to a fused mass - crushing the mass into powder - adding 6.0 mg of C. sub sixty fullerene to the powder - heat treating the mixture in a carbon crucible around 360°C for 3 hrs under vacuum - finally melting the mixture at a temperature around 680°C for 35 minutes under controlled atmosphere of nitrogen gas. The glass obtained was a monolithic sample having C. sub sixty fullerene dispersed in the form of small clusters.
Example - 2
The fullerene containing glass in an amount 35 gm was also prepared by using mixture of ingredients like 0.16 mole of B2C3, 0.035 mole SiO2, 0.02 mole of AI2O3 and .015 mole of PbO - melting the batch in a platinum crucible in a furnace at around 650°C - cooling the molten mass in the form of lump crushing the same into powder - adding 3 mg C. sub sixty fullerene to this host material - heat treating the mixture in a carbon crucible at 380°C for 2 hour under vacuum - then melting the mixture at 750°C for 20 mins to a
vitreous liquid under controlled atmosphere of nitrogen. The glass obtained showed a pink tint.
Example - 3
In an another trial, 80 gm of the glaiss was prepared by using a batch mixture ofO.06 mole of ZnO, 0.25 mole of PbO - reacting the mixture with 0.3 mole of P2O5 - sintering th reaction product in an alumina crucible to a consolidated mass at a temperature around 600C in a furnace - crushing the lump into granules - adding 8 mg of C. sub sixty fullerence to the latter - heat treating the fullerene containing mixture in a carbon crucible at around 370°C for 1 hrs under vacuum - finally melting the mixture to a vitreous melt around 660°C for 0.5 hr under controlled atmosphere of helium gas. The glass obtained was monolithic sample with homogeneous dispersion of C. Sub sixty fullerene.
Example - 4
Another sample of the glass weighing around 60 gms was prepared by using a mixture of ingredients like 0.27 mole PaOs and 0.27 mole of ZnO - adding 0.06 mole of PbO - sintering the mixture in an alumina crucible at 550°C in a furnace to a solid mass - crushing the product into powder - adding 6 mg of C. Sub sixty fullerene to a resulting powder - mixing them intimately in a vibrator - heat treating the same around 380°C in a graphite crucible under vacuum for one and half hour - finally melting the mass at 770°C for 25

minutes under controlled atmosphere of helium gas. The glass sample obtained had a light pink tint with particulate dispersion of C. Sixty fullerene. Example - 5
About 35 gm of another glass was prepared by using a batch mixture consisting of ingredients like 0.15 mole B2O3, 0.06 mole of PbO, 0.06 mol of PbF2 and 0.03 mole of ZnO - melting the batch ina platinum crucible to a sintered mass at a temperature around 700°C - converting the mass in the form of granules - adding 3 mg of C. Sub sixty fullerene to the former -mixing the components intimately - heat treating the mixture in graphite crucible at around 370°C for 1 hr under vacuum - then melting the mixture by increasing the temperature up to 725°C for 20 mins. The glass obtained showed a faint pink tint.
Example - 6
C. sub sixty fullerene containing glass was also prepared in a quantity of 50 gms by using a batch mixture of 0.023 mole of AI2O3, 0.3 mole of ZnO, 0.03 mole of PbO and 0.01 mole of Na2O -reacting the mixture with 0.30 mole of P2O5 - sintering the reaction product to a consolidated mass at a temperature around 550°C - cooling the sintered mass to room temperature - crushing the same into granules - adding 5.0 mg of C. sub sixty fullerene to the host granules - mixing the same in a vibrator - heat treating the resultant mixture in a graphite crucible around 380°C for 11/2 hrs under vacuum - finally melting the same at around 880°C for 30 mins under controlled atmosphere of mixture
nitrogen and argon gases to form glass. The glass obtained was a monolithic sample of 20 mm thick.
Example - 7
40 gms of similar glass was also prepared by using a batch mixture of 0.12 mole of PbO, 0.14 mole of B6O3 and 0.045 mole of SiO2 - heat treating the mixture in an alumina crucible at around 550°C for 5 hour to transform into a sintered mass - crushing the product into powder - adding 3 mg of C. sub sixty fullerene to the powdered host - mixing the two components intimately -heat treating the mixture in a carbon crucible at around 390°C for 1 hr under vacuum - finally melting the same by raising the temperature to 730°C for 30 mins under controlled atmosphere of argon to form glass with homogeneous dispersion of C. sub sixty fullerene. A light pink coloured glass was obtained.
Example - 8
35 gms of such glass was also prepared by making a batch mixture of 0.03 mole of ZnO, 0.12 mole of PbO and 0.15 mole of B2O3 - melting the batch in a an alumina crucible at around 700°C to glassy mass - crushing the glassy mass into pieces - adding 3 mg of C. sub sixty fullerene to the former - heat treating the new mixture in a carbon crucible at around 380°C for 1 hr in a closed furnace under vacuum - finally melting the material at about 750°C for 20 mins under a constant flow of nitrogen. The melt was cooled - the glass obtained did show purple tint.
Transparent monolithic samples of C. sub sixty fullerene - glass composite prepared in different size and shapes using varied glass compositions and with different concentrations of the C. Sub sixty fullerene as described above, showed the existence of homogeneously dispersed C. sub sixty fullerene in the glass both as isolated molecules and small clusters, as have been revealed by optical absorption study as shown in Fig. 1 of the drawing accompanying the specification. The single peak at frequency 625nm indicates the presence of C. sub sixty fullerene in the entire matrix . Any heterogeneity would have resulted into more number of peaks. The main advantages of the invention are:
The present method for preparing C. sub sixty fullerene-glass
composite can be used to prepare bulk monolith useful in actual
device applications.
1. It is superior to sol-gel process both in respect of homogeneous
dispersion and protection of C. sub sixty fullerene from
environmental degradation.
2. The method is simple and cost effective.

We Claim :
1. An improved process for preparing transparent monolithic glass of carbon
sub sixty fullerene - glass composite , said process characterized in that
heating at a temperature range of 400-900° C a weather resistant glass
composition such as herein described , having melting point below 800 °
C to obtain a solid mass , crushing the solid mass into granules/powder,
adding carbon sub sixty fullerene to the granules/powder in the range of
0.05-0.1 overall wt% , mixing the two intimately , heat treating the mixture
in a carbon crucible at a temperature ranging 350 -390 ° C under vacuum ,
melting the mixture at a temperature in the range of 600-800° C under inert
gas atmosphere as described herein , cooling the melt to get desired
transparent monolithic glass.
2. An improved process as claimed in claim 1 wherein a glass composition
used is 0-50 mole% of phosphorous pentoxide (P2O5), 0-40 mole % of boron oxide (B2O3), 0-30 mole % of bismuth oxide (Bi2O3), 0-1 mole % silicon dioxide (SiO2), 0-1 mole % of aluminium oxide (AI2O3), 10-45.5 mole % of zinc oxide (ZnO), 10-40 mole% of lead oxide (PbO), 0-0.1 mole% of tin dioxide (SnO2), adding to the mixture 0-5 mole % alkali metal oxide (M2O where M = Na, K, Li).
3. An improved process as claimed in claims 1- 2 wherein phosphorous
pentoxide (P2Os) used is either as it is or from compounds selected
from ammonium dihydrogen phosphate, diammonium hydrogen
phosphate, phosphoric acid.
4. An improved process as claimed in claims 1 - 3 wherein boron oxide
(B2O3) used is selected from compounds boric acid, sodium metaborate.
5. An improved process as claimed in claims 1-4 wherein lead oxide (PbO)
used is selected form Lead carbonate, red lead.
6. An improved process as claimed in claims 1-5 wherein the bismuth oxide
(Bi2O3) used is either as it is or as compounds selected from bismuth
nitrate, bismuth chloride, bismuth hydroxide.
7. An improved process as claimed in claims 1-6 wherein alkali metal oxide
IvbO (M=Na, K, Li) used is in the form of respective carbonates.
8. An improved process as claimed in claims 1 - 7 wherein the inert gas
used is chosen from Argon, Nitrogen, Helium, a mixture thereof.

Documents:

622-del-2001-abstract.pdf

622-del-2001-claims.pdf

622-del-2001-correspondence-others.pdf

622-del-2001-correspondence-po.pdf

622-del-2001-description (complete).pdf

622-del-2001-drawings.pdf

622-del-2001-form-1.pdf

622-del-2001-form-18.pdf

622-del-2001-form-2.pdf

622-del-2001-form-3.pdf

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Patent Number

230763

Indian Patent Application Number

622/DEL/2001

PG Journal Number

11/2009

Publication Date

13-Mar-2009

Grant Date

27-Feb-2009

Date of Filing

29-May-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	RADHABALLABH DEBNATH	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA, 700032, INIDA.
2	RAMPADA SAHOO,	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA, 700032, INIDA.
3	SHYMAL KANTI BHATTACHARY	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA, 700032, INIDA.

PCT International Classification Number

C03C 3/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA