Abstract: The amount of residual carbon and hydroxyl groups in a synthetic quartz powder made by a wet process is reduced by baking the synthetic quartz powder in a low pressure atmosphere. Quartz glass crucibles made using the synthetic quartz powder have low bubble contents, and are particularly suited for growing single crystals.

Abstract: A low reflection film comprising silica fine particles and a binder in a weight ratio proportion of 60:40 to 95:5 is obtained by mixing starting fine particles comprising at least non-aggregated silica fine particles with a mean particle size of 40-1000 nm and/or linear (chain-like) aggregated silica fine particles with a mean primary particle size of 10-100 nm, a hydrolyzable metal compound, water, and a solvent, hydrolyzing the hydrolyzable metal compound in the presence of the starting fine particles, and then coating the prepared coating solution onto a glass base substrate and subjecting it to heat treatment.

Abstract: Silica sols exhibiting desirable yield-dilatancy are fabricated. A mixture comprising silica, water, and a pH-adjusting agent is provided, and the mixture is shear-mixed. The desirable properties of the resultant sol are attained by using a concentration of pH-adjusting agent that provides a viscosity within a particular range during shear mixing. The requisite pH range, however, changes depending on the properties of the silica mixture. A discovered technique for determining this changing pH range is by selecting the pH based on the silica surface area per unit volume of the mixture.

Abstract: A multicomponent particulate gel includes 80-100 mole % SiO2, 1-10 mole % X2O, 1-10 mole % YO, 1-15 mole % Al2O3, and 0.1-5.0 weight % Er2O3,where X represents lithium, sodium, potassium, or mixtures thereof and Y represents calcium, barium, magnesium, lead or mixtures thereof, and the ratio of Al2O3 to (X2O+YO) is between about 0.9 and about 2.5. A process of manufacturing the gel includes hydrolyzing alkoxide derivatives of silicon, aluminum, erbium, lithium, sodium, potassium, calcium, barium, magnesium, lead or mixtures thereof in water to generate their respective hydroxide derivatives; polymerizing the hydroxide derivatives to produce a gel slurry comprising an essentially silica network; and drying the gel slurry to produce the gel.

Abstract: There are disclosed the following three types of optical recording film:

Abstract: Deuterium oxide, D2O, also called heavy water, is used for the hydrolysis of silanes and metal compounds. The D2O-hydrolyzed silanes polycondense much easier than H2O-hydrolyzed silanes, resulting in a fast Si—O—Si network build up. The most important feature of using D2O is that the final materials are 100% free of O—H and the residual O—D bond does not have an absorption peak in the wavelength range of 1.0 to 1.8 &mgr;m, which is crucial in reducing optical loss at the wavelengths of 1.3 and especially 1.55 &mgr;m. O—H free sol-gel materials with low optical loss have been developed based on this process. D2O may be applied in all kinds of hydrolysis-processes, such as the sol-gel process of silanes and metal compounds, the synthesis of polysiloxane, and may be extended to other silica and metal-oxides deposition processes for example, flame hydrolysis deposition (FHD) whenever water is used or O—H bond involved.

Abstract: The present invention provides a two stage process of thermal separation of CFCs and HCFCs followed by vitrification of the waste into a commercially viable glass. In the first stage, the hydrogenated compounds are reacted at elevated temperature with water and a metal oxide such as calcium oxide to form a halide salt and carbon dioxide. In the second stage of the process, the brine slag is reacted at elevated temperature with the carbon dioxide from stage one and glass-forming raw materials such as silicon dioxide to produce a glass. The final glass product incorporates the halide into the glass.

Abstract: The invention relates to the catalytic activity and selectivity of microporous, amorphous glasses of mixed metal oxides and the application thereof in the form of shape selective, heterogeneous catalysts. Microporous, amorphous mixed metal oxides (glasses) can be formed by polycondensation of soluble metal compounds. These new materials show a temperature stability up to 800° C. These amorphous glasses shown in heterocatalytic reactions selective oxidation, hydrogenation, hydrocracking and condensation catalysis.

Abstract: A glass-impregnated, fiber-reinforced ceramic comprises a ceramic matrix having open voids, inorganic fibers embedded in the ceramic matrix in a regular or irregular orientation, and a glass matrix filling up the open voids in the ceramic matrix. The glass-impregnated, fiber-reinforced ceramic is manufactured by a manufacturing method comprising the steps of forming a fiber-reinforced ceramic comprising the ceramic matrix having open voids, and inorganic fibers embedded in the ceramic matrix, impregnating the fiber-reinforced ceramic with a glass precursor solution containing a glass precursor to stop up the open voids of the ceramic matrix with the glass precursor solution, and subjecting the fiber-reinforced ceramic impregnated with the solution to a heat treatment.

Abstract: A raw material mixture, which has a glass composition containing a salt or an oxide of a flame reaction metal, is heated, and an intermediate base material, in which the salt of the flame reaction metal, or the like, has been thermally decomposed and which is in a temporary sintered state or a fused glass state, is thereby formed. The intermediate base material is ground, and a ground material is thereby obtained. The ground material is mixed together with a liquid and, optionally, a binder, and a viscous flame reaction material is thereby formed. The viscous flame reaction material is supported on a substrate and heated to a temperature, which is not lower than a vitrification melting temperature of the viscous flame reaction material. In this manner, the flame reaction material is fusion bonded to the substrate. Generation of a thermal decomposition gas in the baking step is thus restricted, and the carrying of the flame reaction material on the substrate is carried out appropriately.

Abstract: A method of a fabricating silica glass by sol-gel process is provided. The method includes mixing silica, a binder, a dispersing agent and a gelling agent, and forming a sol without air bubbles; injecting the sol into a mold, the injection of the sol into the mold being controlled by the pressure of an inert gas; gelating the sol injected into the mold and demolding the gel; and drying the demolded gel, and thermally-treating the dried gel. Therefore, incorporation of impurities and air bubbles during injection of a sol into a mold is minimized, and injection amount and injection rate of the sol can be controlled.

Abstract: A method of a fabricating silica glass by sol-gel process is provided. The method includes mixing silica, a binder, a dispersing agent and a gelling agent, and forming a sol without air bubbles; injecting the sol into a mold, the injection of the sol into the mold being controlled by the pressure of an inert gas; gelating the sol injected into the mold and demolding the gel; and drying the demolded gel, and thermally-treating the dried gel. Therefore, incorporation of impurities and air bubbles during injection of a sol into a mold is minimized, and injection amount and injection rate of the sol can be controlled.

Abstract: The invention relates to the catalytic activity and selectivity of microporous, amorphous glasses of mixed metal oxides and the application thereof in the form of shape selective, heterogeneous catalysts. Microporous, amorphous mixed metal oxides (glasses) can be formed by polycondensation of soluble metal compounds. These new materials show a temperature stability up to 800° C. These amorphous glasses show in heterocatalytic reactions selective oxidation, hydrogenation, hydrocracking and condensation catalysis.

Abstract: A method for making glass and particularly ceramic frits, comprising the steps of: introducing in a wet grinding unit, after a metering step according to chosen proportions, materials which constitute a mixture to be melted, to produce a slurry; screening and collecting said slurry in a storage tank; introducing the collected slurry in a melting furnace to make a liquid component of the slurry evaporate; and forming a melted paste of vitreous material, adapted to be converted into a ceramic frit.

Abstract: A method for producing a dopant doped high pure silica glass comprising the steps of: preparing powder by dispersing silica particles into a dispersion medium; adding a dopant containing gas; drying, heating and pulverizing the same in sequence to produce dopant doped silica powder; and, producing a dopant doped silica glass by using the silica powder produced by said powder preparing step as a starting substance.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing a deionized water with a fluorine compound and a dispersion agent to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fumed silica; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the sol at the ambient temperature to stabilize silica particles; and, (e) removing air voids from the sol and adding a gelation agent.

Abstract: Disclosed is a method for controlling a heat treatment in the process of fabricating a high purity silica glass via a sol-gel process using a low temperature heater having an inhalation line and an exhaust line. Accordingly, the method includes the steps of (a) identifying whether or not the diameter of the exhaust line is varied; (b) controlling the mass flow of the process gas according to the changed diameter of the exhaust line in step (a); (c) measuring an exhaust gas velocity discharged through the exhaust line; (d) comparing the exhaust gas velocity measured in the step (c) with the exhaust gas velocity after the scale of the exhaust line is varied; and, (e) repeating steps (b)-(d) if the comparison result in step (d) is different.

Abstract: In a method of making a high-quality silica glass, a rare earth element that is a substance making a great contribution to the index of refraction is introduced therein together with aluminum for stabilizing the glass. An alkoxide of aluminum or its derivative is used as the starting material for preparing a boehmite sol. A salt of at least one element selected from rare earth elements or a solution in which the salt is dissolved and the boehmite sol are mixed with a silica sol, whereupon the sols are vitrified.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing deionized water with a monomer and a dimer to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fused silica and a dispersion agent; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the dispersed sol at the ambient temperature to stabilize silica particles, and removing air voids from the sol; and, (e) adding a polymerization initiator and a gelation agent to the aged sol.

Abstract: There is provided a method of manufacturing a glass plate with a light-transmissive colored film using a coating solution including a metal salt and a metal alkoxide, the light-transmissive colored film having a coloring effect due to a metal oxide which will not be impaired even if the amount of the added metal alkoxide is increased, and being highly resistant to wear and chemicals.

Abstract: A synthetic quartz powder obtained by calcining a powder of silica gel, characterized in that white devitrification spots having sizes of larger than 20 &mgr;m in diameter formed in an ingot obtained by vacuum melting the synthetic quartz powder at a temperature of from 1780 to 1800° C. to form an ingot, followed by maintaining the ingot at a temperature of 1630° C. for 5 hours, are at most 10 spots/50 g.

Abstract: The invention reflects discovery of a liquid phase doping technique that, unlike previous techniques, exhibits very little fluorine depletion upon subsequent heating. The invention involves the steps of providing a silica sol comprising a tetraalkylammonium hydroxide and a di-, tri-, or tetraalkylammonium fluoride, the sol having pH of about 10 to about 14, adding a gelling agent to the sol to induce gelation, casting or extruding the sol to form a gel body, and then drying, heat treating, and sintering the body. Advantageously, the fluorine-containing compound is tetramethylammonium fluoride.

Abstract: A silica body useful for forming an optical fiber preform exhibits an ultimate strength of at least 20 MPa at 10 wt. % water loss. The body attains this strength, it is believed, by precipitation of silica at the contact sites of adjacent silica particles, thereby forming neck regions. The resultant network provides the strength to the gel body, such that the body is capable of being dried under more severe conditions than a gel body formed by previous sol-gel methods and is also more robust toward handling. The controlled precipitation is attained by inducing gelation and initiating drying at a pH of about 10.5 or higher, at which silica remains highly soluble. By gelling and drying at this pH level, the solubilized silica appears to precipitate in a controlled manner at the point of contact of adjacent silica particles, since such sites are the minimum free energy sites for precipitation.

Abstract: There is provided a process for producing an aerogel which comprises lowering a pH of a water glass solution to obtain a sol, gelling the sol to obtain a hydrogel, replacing water in the gel with an organic solvent, reacting the gel with a hydrophobilizing agent having hydrophobic groups as well as functional groups reactive with silanol groups in liquid phase, followed by supercritically drying; or hydrophobilizing and supercritically drying the resultant gel at the same time. Preferably, the hydrogel is prepared by ion exchanging alkali metals in the water glass solution using an ion exchange resin to obtain a sol which is subjected to suspension polymerization.

Abstract: A process for preparing silica gel is disclosed. The silica gel is produced by immersing a base in silica sol, drying the impregnated base in a mixed solution of an alkali silicate and an alkali hydroxide, removing the impregnated base form the mixed solution, heating the impregnated base, and subsequently treating the impregnated base with an acid. A sufficient amount of silica gel for use as a dehumidifying element can be produced through a single series of treatments.