Abstract: A silica-based substrate includes a glass phase and a dispersed phase having carbon, such that the silica-based substrate has a thickness of at least 10 gm. Also disclosed is a method of forming a silica-based substrate, the method including contacting a porous silica soot preform with an organic solution having at least one hydrocarbon precursor to form a doped silica soot preform and heating the doped silica soot preform in an inert atmosphere to form the silica-based substrate.

Abstract: The method of making borosilicate glass with a surface having reactive SiOH groups on it includes preparing a borosilicate glass melt and dissolving at least 30 mMol per liter of water in the borosilicate glass melt. The borosilicate glass contains from 70 to 87 percent by weight, SiO2; from 7 to 15 percent by weight, B2O3; from 0 to 8 percent by weight, Al2O3; from 0 to 8 percent by weight, Na2O and from 0 to 8 percent by weight of K2O. The borosilicate glass with the easily modified reactive surface can be used as a substrate for chemically covalent immobilization of reactive substances. This substrate can be used to make a biochemical chip, such as a DNA or gene chip, or dirt-proof window glass.

Abstract: Using sol-gel techniques, an optical gain medium has been fabricated comprising a glass ceramic host material that includes clusters of crystalline oxide material, especially tin oxide, and that is doped with active ions concentrated at the clusters. The active ions are preferentially located at the nanoclusters so that they experience the relatively low phonon energy of the oxide and are insensitive to the phonon energy of the host. A host with a high phonon energy, such as silica, can therefore be used without the usual drawback of reduced carrier lifetimes through enhanced nonradiative decay rates.

Abstract: Pyrogenically prepared silicon dioxide with the following physicochemical properties: 1. Average particle size (D50 value) D50?150 nm (dynamic light scattering, 30 wt %) 2. Viscosity (5 rpm, 30 wt %) ??100 m·Pas 3. Thixotropy of Ti (?(5 rpm))/(?(50 rpm))?2 4. BET surface area 30-60 m2/g 5. Compacted bulk=100-160 g/L 6. Original pH?4.5 that can be used for the preparation of dispersions and glass bodies.

Abstract: Use of an essentially impermeable transfer belt (16) for a soft tissue paper machine for conducting a soft tissue web (1) through a shoe press nip in the press section of the paper machine, and from the shoe press nip to a Yankee cylinder (5) in the dryer section of the paper machine in a closed draw. The Yankee cylinder forms, together with a transfer means (17), a transfer nip for transferring the soft tissue web from the transfer belt to the Yankee cylinder.

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: A sol-gel process for fabricating bulk, germanium-doped silica bodies useful for a variety of applications, including core rods, substrate tubes, immediate overcladding, pumped fiber lasers, and planar waveguides, is provided. The process involves the steps of providing a dispersion of silica particles in an aqueous quaternary ammonium germanate solution—typically tetramethylammonium germanate, gelling the dispersion to provide a gel body, and drying, heat treating, and sintering the body to provide the germanium-doped silica glass.

Abstract: A sol-gel method of preparing a powder for use in forming a glass is provided, along with methods of preparing glasses and glass fibers from the powder. The inventive method allows for the incorporation of a wide range of elements and compositions into a homogeneous glass or glass fiber that is substantially free of hydroxide groups. In addition, dopants incorporated into glasses prepared by the inventive method are uniformly distributed throughout the glass structure.

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: 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: 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: The invention comprises devices composed of at least one microscopic hollow tube having a wall of single or multiple layers with a thickness of at st one nanometer and a diameter of at least 5 nanometers. The walls of the tubes can be formed from a wide variety of materials, some of the preferred materials include metals, polymers, carbon, ceramics, glasses. If the space between the tubes is filled, the tubes become channels in a monolithic or composite body. The channels can have a random or ordered orientation. The interior of the tube walls can be coated with a desired material such as a catalyst and also may have depressions or elevations therein that were imparted to the fibers upon which the tubes are formed. The wall layers may be porous for the purpose of removing the fiber therethrough. Microtubes and microtube devices may be interfaced with the macroscopic world in a number of ways.

Abstract: The invention provides an alternative to conventional sol-gel methods that utilize undesirably high amounts of a stabilizing agent such as TMAH and a gelling agent such as methyl formate. The method involves the steps of (a) providing a colloidal silica dispersion containing a stabilizing/gelling agent, where only a portion of the molecules of the agent ionize, and (b) subsequently adding to the silica dispersion a pH-reducing additive. The stabilizing/gelling agent has a dual function. The agent, e.g., an amine, initially acts as a stabilizer in the silica dispersion in that a portion of its molecules ionize, while an appreciable amount of the agent remains non-ionized. The agent later transforms in situ to a gelling agent upon addition of a pH-reducing additive. Specifically, as the pH-reducing additive lowers the pH to values at or around the pK.sub.

Abstract: There are provided tube-shaped glass monolith fabricating apparatus and method using a sol-gel process. In the tube-shaped glass monolith fabricating method using a tube-shaped glass monolith fabricating apparatus which has an upper mold including cylindrical portions of different sizes, a lower mold including a first lower cylindrical portion inclined toward the center thereof by a predetermined degree and a second lower cylindrical portion having a vacuum releasing hole, a cylindrical central mold for forming a tube-shaped glass, and a rod-shaped rod, the lower mold, the central mold, and the rod are assembled and a sol is poured in the central mold. Then, an unmixable liquid is poured on the sol, and the upper mold is assembled to the central mold. The sol is gelled in the central mold, the upper mold is removed, a cap is opened to release vacuum, and the rod is removed.

Abstract: The invention is directed to a method for producing low sintering fine-particle multicomponent glass powder having a particle size of the primary particle in the nanometer range. The method utilizes microemulsion techniques with subsequent separation of the particles out of the emulsion and calcination for utilization as glass flow having a sintering temperature <900.degree. C. or in a glass flow, for generating thin transparent layers or for generating color decorations on glass, glass ceramic or ceramic substrates after adding a coloring pigment to the glass flow. The microemulsion for producing the nanoscale glass powder particles is generated from a nonionic ambiphilic emulsifier with a component of 10 to 15 percent by weight on the emulsion, from an oil phase having a portion of 50 to 70 percent by weight and a glass precursor-containing aqueous salt solution having a portion of up to 31.3 percent by weight with salt contents of up to 45 percent by weight.

Abstract: UV absorbing glass is prepared by mixing ultrafine colloidal cerium oxide with glass-forming substances during the fabrication of the glass. An aqueous colloidal dispersion containing 1-20 weight percent 10-20 nm cerium oxide particles, optionally including a binder, is admixed with silica sand, and the sand is dried, melted and cooled to give a relatively clear UV absorbing glass containing 0.3-2 weight percent cerium oxide.

Abstract: A method for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters.

Abstract: A method of manufacturing an optical element which is a beam splitter. A first and a second prism, the second prism having a beam splitting film formed on the surface, are contacted together with the hydrolysis product of a metal or silicon alcoholate, thereby forming a bond of the hydrolysis product of the alcoholate between the first and second prism.

Abstract: A method for manufacturing a glass is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing at least one compound selected from the group consisting of an acid, an ammonium salt and an alkylammonium salt to precipitate the metal salt as microcrystals in the pore. Also, a method for manufacturing a glass for use as a gradient index optical element is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing a salt of a metal component different from the above-mentioned at least one component and at least one compound selected from the group consisting of an acid and a salt to provide the metal components with concentration distributions.

Abstract: Bent sol-gel produced tubing is straightened by drawing, with tensile force and operating temperature to result in minimal plastic flow, so that size reduction is small. The method is usefully applied to reject recovery in the preparation of overclad tubes, which as encompassing closely-fitting core rods, form the composite preform from which optical fiber is drawn.

Abstract: Incidence of breakage in optical fiber drawn from sol-gel produced preforms is reduced by treatment of the still-porous glass by use of a chlorine-containing, oxygen-free gas mixture. Improved satisfaction of proof-rest requirements to at least 100 kpsi is assured by size reduction of unassimilated discrete particles in the fiber.

Abstract: Optical fiber drawn from preforms including sol-gel-derived glass is found to contain small refractory particles of the order of a micron in size. These particles initiate fiber breaks with the result that fiber may not meet proof-test tensile strength requirements. An effective separation method relies upon density and/or size difference from suspended sol particles for separation in the ungelled sol. A preferred separation procedure is centrifugation.

Abstract: A glass preform for an optical fiber containing a dopant in a core portion at a high concentration is produced by providing a glass tube, forming a coating film of a sol-gel solution containing a dopant compound on an inner wall of the glass tube, vitrifying and collapsing the glass tube having the coating of the sol-gel solution to obtain a glass rod.

Abstract: A process for producing flakes of glass. The process is started by applying a solution containing an organic metal compound to a substrate. The solution is dried and peeled from the substrate. The resultant film is sintered. There is also disclosed an apparatus for producing flakes of glass. The apparatus comprises means 2 for applying solution 1 containing an organic metal compound to a substrate 3 taking the form of a loop, means 4 for drying the film created by the solution containing the organic metal compound, and means 5 for collecting flakes obtained by peeling the dried film from the substrate. The substrate forms a circulatory continuous conveyance path which passes through the applying means, the drying means, and the collecting means in succession.

Abstract: A method of manufacturing distributed index optical elements is disclosed. The method comprises a step of preparing silica sol including at least one of metal dopants, a step of dipping, after subjecting the silica sol to a gelling treatment, the silica gel in an elute into which a part of metal constituents other than silicon including in the gel is selectively eluted, and a step of drying and sintering the silica gel.

Abstract: Relatively large bodies of low-alkali silicate and other glass can be prepared conveniently by a particulate sol-gel process. The glass comprises at least 85 mole % SiO.sub.2, 1-12 mole % oxide of one or more of Li, Na, K, Rb, Cs, Ti and Zr, 0-6 mole % of oxide of Al, and optionally at most 2.5 mole % of oxide of elements other than Si, Li, Na, K, Rb, Cs, Ti, Zr and Al. The process comprises forming particles from a first sol that comprises Si and one or more of Li, Na, K, Rb, Cs, Ti and Zr, and optionally additionally comprises Al. The process further comprises forming a second sol by dispersing the particles in an aqueous liquid, gelling the second sol, and heat treating the resulting gel body such that the glass results.

Abstract: A novel method is proposed for the preparation of a transparent fused silica glass body co-doped with a rare earth element and aluminum each in a high uniformity of the dopant distribution. The method comprises the steps of: (a) flame-hydrolyzing a silicon compound and an aluminum compound in an oxyhydrogen flame to form a porous silicon oxide body containing aluminum; (b) soaking the porous body having a specified bulk density with a solution of a rare earth compound; (c) drying the solution-soaked porous body; and (d) sintering and vitrifying the dried porous body into a transparent glass body.

Abstract: The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

Abstract: Lowered cost fabrication including preparation of large bodies of void-free, high-silica glass, depends upon gellation of an aqueous sol of colloidal silica particles, followed by drying and firing of such gel. Freedom from cracks in the dried gel is the consequence of included polymeric material which wets the particles. The polymeric material is removed by thermal decomposition attended upon temperature attained in firing.

Abstract: A method for preparing a silica glass article of improved purity is provided. The article is prepared by a sol-gel method and is then heat treated to a selected temperature between about 1500.degree. and 2200.degree. C. and maintained at the selected temperature for a predetermined period of time sufficient to remove silica crystals, inclusions, microcracks and bubbles. The resulting silica glass articles have improved purity and can be used as photomask substrates or as preforms for optical fibers.

Abstract: A process for preparing an oxidation resistant black glass having the empirical formula SiC.sub.x O.sub.y, wherein 0<x.ltoreq.2.0 and 0<y.ltoreq.2.2. The process comprises reacting cyclosiloxane monomers to effect the bonding of one vinyl carbon atom to a silicon, curing the product at not greater than 250.degree. C., and pyrolyzing at about 800.degree.-1400.degree. C. in an atmosphere containing a sufficient amount of oxygen to reduce the carbon content of the black glass to a desired level.

Abstract: A process for the preparation of monoliths of aerogels of metal oxides, which aerogel is either constituted by one single oxide, or is constituted by a mixture of oxides, is disclosed, which process consists of the following operating steps:(a) the relevant metal alkoxide(s) is/are mixed with water in the presence of a catalyst of acidic character;(b) the so obtained mixture is hydrolysed;(c) a colloidal suspension of the oxide of a metal equal to, or different from, the metal(s) used in the (a) step is added to the hydrolysate;(d) the so obtained colloidal solution is caused to turn into a gel (gelation) having the desired shape and dimensions;(e) the gel is washed;(f) the gel is dried at values of temperature and pressure which are higher than the critical pressure and temperature values of the solvent used for the washing.

Abstract: A rare earth element-doped glass in which the rare earth element is homogeneously doped is produced by a method coprises hydrolyzing a metal alkoxide of the formula:M(OR).sub.4wherein M is a metal and R is an alkyl group in a liquid medium selected from the group consisting of alcohols and water in the presence of a compound of a rare earth element and condensing the hydrolyzed material to form a rare earth element-doped glass.

Abstract: A substantially dehydroxylated glass is formed by impregnating a dry porous silica gel with a nitrogen-containing organic compound in an organic solvent capable of solubilizing that compound. The impregnated gel is then sintered in a non-oxidizing atmosphere to form a substantially dehydroxylated, fully-densified silica glass. The gel is typically formed by a sol-gel process. The nitrogen-containing organic compound can be guanidine compounds, urea, or mixtures thereof.

Abstract: A silica-based glass rod is inserted into a space portion of a mold. Then, a slurry, which is obtained by dispersing a silica glass powder material in pure water, is poured into a molding space between the glass rod and the inner surface of the mold, whereby a porous glass shaped body is formed around the glass rod. Drying this shaped body results in a silica glass base material which includes the glass rod and the porous glass shaped body surrounding the same.

Abstract: In accordance with the present invention, the dopant within one gradient index optical element has two independent concentration distributions. Particularly to use the present invention to obtain a gradient index optical element having an excellent chromatic aberration correction ability, it is only needed to make such dopant distributions as shown in the previously stated Japanese Patent Application No. 280897/1989. However, as to the doping of a dopant into a porous body, there is a limit in the amount which can be doped. This is a disadvantage of the molecular stuffing method, but the reason for this is that the dopant must be supplied into the holes as a solution and it is largely restricted by the solubility of the dopant in the solvent. In addition, since the intra-hole fixing of the dopant depends on the solubility difference by temperature or that by solvent exchange, it is further restricted.

Abstract: A method for producing a glass preform for use in the fabrication of an optical fiber, which comprises adding fluorine to a soot preform in an atmosphere comprising a fluorine-coating compound at a temperature at which the soot preform is in the porous state and then keeping or inserting it in an atmosphere containing a fluorine-containing compound at a higher temperature to vitrify it to form a glass preform, from which glass preform, an optical fiber homogeneously containing fluorine is fabricated.

Abstract: A method is disclosed for improving the rupture strength of a glass material which comprises coating an unannealed glass material with a tractable preceramic coating material capable of pyrolyzing to form a ceramic coating at a temperature not exceeding the annealing temperature of the glass material and heating the coated glass material to a temperature sufficiently high to permit pyrolysis of the pre-ceramic polymer without exceeding the annealing temperature of the glass for a period of time sufficient to form a ceramic coating on the surface of the glass material.

Abstract: A process for easily producing a silica glass plate having an internal refractive index distribution suitable for a planar optical waveguide involves carrying out the following steps.(a) A porous silica gel plate produced by a sol-gel method is kept in a reactor, the pressure of which is reduced to a substantially vacuum state.(b) Germanium tetrachloride gas is introduced into the reactor at a partial pressure appropriate to establish an absorption equilibrium between a desired concentration of germanium tetrachloride in said porous silica gel plate and a partial pressure of germanium tetrachloride introduced.(c) The partial pressure of germanium tetrachloride in step (b) is reduced so as to desorb germanium tetrachloride from the surface of the porous silica gel plate.(d) The porous silica gel plate having a described concentration distribution is brought into contact with water within or outside the reactor so as to fix the distribution.

Abstract: This invention relates to production of high purity fused silica glass doped with titania through oxidation or flame hydrolysis of a gaseous mixture and containing rutile crystals comprising a vaporizable, silicon-containing compound. Titanium-2-ethylhexyloxide, titanium cyclopentyloxide, and a titanium amide, or a combination thereof, constitute the operable titanium-containing compounds.

Abstract: This invention relates to the production of high purity fused silica glass through oxidation and/or flame hydrolysis of a halide-free, organosilicon-R compound in vapor form having the following properties:(a) producing a gas stream of a halide-free silicon-containing compound in vapor form capable of being converted through thermal decomposition with oxidation or flame hydrolysis to SiO.sub.2 ;(b) passing said gas stream into the flame of a combustion burner to form amorphous particles of fused SiO.sub.2 ;(c) depositing said amorphous particles onto a support; and(d) either essentially simultaneously with said deposition or subsequently thereto consolidating said deposit of amorphous particles into a virtually nonporous body; the improvement comprising utilizing a halide-free, organosilicon-R compound in vapor form having the following properties:(1) a Si--R bond dissociation energy that is no higher than the dissociation energy of the Si--O bond;(2) a boiling point no higher than 350.degree. C.

Abstract: Disclosed is a method of forming a doped glass body. The glass body is formed by adding a dopant to a glass preform, at least part of which has interconnective pores. The porous preform is immersed in a solution of a salt of the dopant dissolved in an organic solvent having no OH groups. The solvent is removed, and the porous glass preform is heat treated to consolidate it into a non-porous glassy body containing the dopant dispersed throughout at least a portion of the body. An OH-free solvent is selected because of its beneficial effect on the preform during the drying step. Whereas OH-containing solvents such as water and alcohol caused cracking and/or flaking of the outer surface of the porous preform following the drying step, an undamaged surface is formed by the present invention.

Abstract: A silica glass powder suitable for the production of a silica glass body product of a low silanol content, which is obtained by baking a dried silica gel powder obtained by a sol-gel method, at a temperature of from 1,000.degree. to 1,400.degree. C., wherein during the baking period, the silica gel powder is baked in a gas atmosphere containing from 10 to 100% by volume of steam for at least 5 hours.

Abstract: In a method of manufacturing a glass article by means of a sol-gel process, a metal alkoxide is hydrolyzed, dehydrated and condensed to obtain a wet gel. A molding container is used for drying and shrinking the wet gel to obtain a dry gel. A bottom wall of the molding container has an inner surface formed with a recess or recesses. The wet gel is dried and shrunk to form a gap or gaps between the inner surface of the bottom wall and the gel on the way of drying and shrinking. The gap or gaps communicate with a space which occurs between an inner surface of a peripheral wall of the molding container and the gel on the way of drying and shrinking.

Abstract: The method includes collapsing a silica-based glass tube to make a preform and drawing fiber from the preform. Prior to collapsing the tube, one or more glass layers are formed on the inner surface of the tube by dip-coating the surface with a sol comprising a metal alkoxide dissolved in an alcoholic or aqueous solvent, polymerizing the sol to form a gel, and drying and sintering the gel. A substantial portion the dopant, present within the sintered gel, diffuses into at least one adjoining glass region. A wide selection of dopant materials, in the form of salts or alkoxides, are readily incorporated by dissolving them in the solvent.

Abstract: A composite substrate is fabricated by applying to a glass fiber substrate a liquid sol-gel composition and then sintering the sol-gel to convert it to the glass phase. A polymeric coating is then applied.

Abstract: In a method of manufacturing a glass article by means of a sol-gel process, a metal alkoxide is hydrolyzed, dehydrated and condensed to obtain a wet gel. A molding container is used for drying and shrinking the wet gel to obtain a dry gel. A bottom wall of the molding container has an inner surface formed with a recess or recesses. The wet gel is dried and shrunk to form a gap or gaps between the inner surface of the bottom wall and the gel on the way of drying and shrinking. The gap or gaps communicate with a space which occurs between an inner surface of a peripheral wall of the molding container and the gel on the way of drying and shrinking.

Abstract: In a flame hydrolysis method for depositing glass soot used ultimately to make optical fiber, a reactant that forms the glassy soot stream is delivered to the torch (20) in liquid form and an ultrasonic nozzle (34) in the torch atomizes the reactant or breaks the reactant into a fine mist without the use of a gas.

Abstract: Silica intended to form the core of an optical-fibre preform is deposited as an unvitrified soot inside a reaction tube, where a non-aqueous solution of dopant precursor(s) is then introduced without removing the tube from the lathe. The precursor(s) of the dopant(s) are dissolved in an anhydrous organic solvent. The solution containing the dopant precursor(s) is introduced into the reaction tube without removing the tube from the lathe so that the solution covers the whole surface of the deposited soot layer and impregnation of the deposited soot layer occurs.

Abstract: This invention relates to the production of high purity fused silica glass through oxidation or flame hydrolysis of a vaporizable silicon-containing compound. More particularly, this invention is directed to the use of vaporizable, halide-free compounds in said production. In the preferred practice, a polymethylsiloxane comprises said vaporizable, halide-free compound.