Abstract: An improved sol-gel method is proposed for the preparation of a transparent silica gel block, in which a deposit of fine silica particles having a controlled particle diameter as prepared by hydrolyzing an alkoxy silane in the presence of ammonia is dispersed in a silica sol solution prepared in an acidic condition and settled therein to form a structure of closest-packing prior to gelation, drying, sintering and vitrification so that silica glass blocks can be obtained with low volume shrinkage from the wet gel in an improved yield without cracks, bubbles and haziness. The improvement can be further enhanced when two separately prepared deposits of silica particles having larger and smaller particle diameters are dispersed as combined in the silica sol solution, especially, when the particle diameter in one deposit is not exceeding 22.5% of that in the other deposit.

Abstract: There is disclosed a method of finishing or smoothing the surface of an optical start rod through the use of plasma heat in an atmosphere which prevents contamination of the rod by residual water. Also there is disclosed a method of fabricating an optical waveguide wherein the start rod has deposited thereon silica soot and which is subsequently consolidated by a plasma.

Abstract: A porous water soluble glass body is formed by sintering powdered glass, compacted to a predetermined density, at a temperature near the glass softening temperature (T.sub.s). The porous body may be impregnated with an organic material for subsequent release at a rate determined by the glass solubility.

Abstract: The present invention is directed to the preparation of hybrid composite bodies composed of an essentially alkali-free, alkaline earth aluminosilicate glass matrix reinforced with SiC whiskers and continuous ceramic fibers.

Abstract: A process for producing silica glass fibers comprising:a step of preparing a silica glass fiber spinning solution by adding a polymerization regulator to a silica sol solution obtained by the hydrolysis and condensation of a silicon alkoxide in the presence of an acid catalyst;a step of spinning the spinning solution into gel fibers by extruding the spinning solution from nozzles;a step of applying an oiling agent containing substantially no water or lower alcohol to the gel fibers;a step of forming a fiber cake by winding the oiled gel fibers on a tube or bobbin;a step of aging the gel fibers constituting the fiber cake;a step of sintering the gel fibers unwound from the fiber cake after the aging step, to form silica glass fibers.

Abstract: Alkali metal silicate glass is mixed with water to form an aqueous alkali metal silicate glass suspension, then dried to form a flexible solid alkali metal silicate glass product which may be heated to above the boiling temperature of water to produce a cellular product. The flexible solid product may be utilized as a flexible film, as an adhesive, a coating agent and a binding agent. The foamed product may be used for thermal and sound insulation.

Abstract: A glass body having a graded (substantially Gaussian) index profile is produced by a process that comprises providing a doped porous body (e.g., having a uniform dopant distribution), heat treating the porous body in a halogen-containing atmosphere, and consolidating the porous body into the glass body. The heat treatment removes a predetermined portion of the dopant from the porous body, such that the radial dopant profile in the glass body differs from the initial profile in the porous body, and such that the Gaussian index profile results. Exemplarily, the porous body is a uniformly germania-doped, VAD-produced, high-silica rod having radially decreasing density, and the heat treatment comprises an 8-hour densification soak at 1300.degree. C. in 20% Cl, 80% He. In a preferred embodiment, silica overcladding is deposited on a graded index core rod produced according to the invention, and fiber drawn from the resulting composite glass body.

Abstract: In a forming a silica glass at low temperature, a fumed silica is added to a hydrolyzed solution of a metal alcoxide. 0.2-5 mol of fumed silica is added to 1 mol of metal alcoxide. Being uniformly dispersed, the solution is gelled and dried to be dry gel and then sintered to be non-porous. This process allows a practically large sized silica glass to be materialized which has been impossible by the previous sol-gel technology. In addition, a further large silica glass can be prepared by adjusting pH value to 3-6 with addition of base in the sol solution.

Abstract: A method for producing ultra-high purity, optical quality, glass articles is disclosed which involves: (1) forming a gel from a silicon-containing organic compound, such as, TEOS; (2) drying the gel to produce granules having a mean particle size of less than about 1 millimeter; (3) fully sintering the granules to produce high purity, artificial sand; (4) casting the artificial sand by conventional techniques, such as, slip casting, to form a high density, porous, green body; (5) drying and partially sintering the green body; (6) fully sintering the green body under vacuum; and (7) hot isostatic pressing ("hipping") the green body. The glass articles produced by the process have higher purity, greater homogeneity, and less IR absorption than existing, commercially available, premium quality, fused silica, glass articles.

Abstract: In one embodiment this invention provides a novel sol-gel process for the production of microporous inorganic oxide glass monolith structures which have improved mechanical strength and optical transparency. An essential feature of the process is the use of trioxane during the gellation phase, to provide a glass monolith with micropores which have uniformity of size and shape.

Abstract: There is disclosed a method of producing an elongated, fiber-reinforced composite having a glass or glass-ceramic matrix and an elongated axial form. A continuous length of fibers is impregnated with glass and the impregnated fiber body consolidated by being pultruded through a die. A combination of axial tension to pultrude the fiber body and sintering pressures exerted by the die result in a composite body of continuous length.

Abstract: Manufacture of optical fibre preforms. A material such as Si, Ge and B.sub.2 O.sub.3 is evaporated in vacuo into a silica tube and is made to condense therein as a viscous liquid which is then oxidized. The operation may be repeated several times with different materials. In this way the tube is clad from within in such a way that the optical index of refraction increases from the periphery inwards. Upon completion of the cladding the tube is collapsed into a rod which is then used for drawing optical fibres.

Abstract: A method of and arrangements for manufacturing glass bodies, in which method a thixotropic suspension, being the starting material for the glass body, is used to form a porous green body which is subsequently subjected to a purification step in a heated gaseous phase and then sintered to form a glass body, the starting material being homogenized and liquefied in a closed elastic mould by subjecting it to sound or ultrasonic, after which the liquid starting material is given the shape of the glass body to be formed and then solidified.

Abstract: Method and equipment for the manufacture of glass bodies in which a porous green body is formed from the starting material for the glass body in the form of a thixotropic suspension, is dried, purified and then sintered, during which process the starting material is transformed into a state with minimum viscosity and homogenized by the introduction of mechanical forces, is poured in the low-viscosity state into a mould of hydrophobic material corresponding to the shape of the glass body to be manufactured and is dried in the mould until a shrinkage of approximately 10% is achieved and then, after removal from the mould, is subjected to further processing steps to produce the glass body.

Abstract: A method for the manufacture of glass bodies, in which a thixotropic suspension, being the starting material for the glass body, is used to form a porous green body which is subsequently purified and sintered, the starting material being liquefied in a mould by subjecting it to mechanical forces, and subsequently freeing it of the influence of the said forces, after which it solidifies again to form a green body.

Abstract: A process is described for manufacturing a product from natural non-transparent quartz (milky quartz), this product being suitable for producing pure quartz glass, as well as a process for processing this product further to produce a shaped body made of pure quartz glass. It is also set forth that this product is suitable as a starting material for growing piezoelectric crystals in an autoclave.

Abstract: An apparatus and method for the continuous production of glass articles characterized by the ability to form a single sheet of glass having two layers of different compositions, double glass panels having an air space between the panels or to produce tubes having either circular or eliptical cross-sections. The apparatus and method utilizes a molding body having a trough means which may be used to divide the glass mass into two cooperating flows over the working surfaces of an upper and lower molding body portions. The glass mass flows downwardly along an outer working surface of the upper body portion onto the inner working surfaces of the lower portion. A nozzle means provided with a ceramic shell or other refractory material may be disposed in an opening provided in the bottom portion of the molding body to provide a means for forming a closed double panel of sheet glass or a tube shaped article.

Abstract: Glass or ceramic products including glass optical waveguides are produced by a vapor phase oxidation process wherein .beta.-diketonate complexes of selected metals having significant vapor pressures at some temperature below their decomposition temperatures are vaporized, transported to an oxidation site in the vapor phase, and reacted in the vapor phase to form particulate metal oxide soot. After capture, this soot can be consolidated by sintering to form e.g. clear glass of a purity suitable for drawing into glass optical waveguide fiber.

Abstract: The invention provides a novel method for manufacturing fused quartz glass by the decomposition and oxidation of a vaporizable silicon compound such as silicon tetrachloride in a plasma flame according to which the quartz glass rod produced contains a controlled amount of hydroxy groups with high reproducibility. The principle of the inventive method consists in the admixture of gaseous hydrogen chloride into the gaseous reactant mixture or in the plasma-supporting gas as the source for the hydrogen atoms to be converted to the hydroxy groups in place of hydrogen gas or water vapor as the hydrogen source. Good proportionality is established between the concentration of the hydrogen chloride in the gaseous feed and the hydroxy content in the resultant fused quartz glass rod.

Abstract: High-silica glasses are formed by sintering a dried gel at temperatures below the liquidus. The gel may be formed by mixing colloidal silica particles or silica-containing liquids with appropriate liquids. Fragmentation of the gel during drying is advantageously avoided by redispersing the dried gel or sol in a liquid to yield a colloidal suspension which is then gelled, dried, and finally sintered below the liquidus.

Abstract: In producing silica glass, which may contain additional metal(s) such as Ti or Zr, from a solution of a silicon alkoxide, mixed with alkoxide(s) of the additional metal(s) where necessary, in water and a hydrophilic organic solvent by shaping the solution into a desired form such as a coating film on a substrate, self-supporting film, fiber or lump when the solution exhibits a suitably high viscosity and sufficiently heating the shaped solution, a water-soluble organic polymeric substance is added to the solution as a viscosity adjusting agent to soon increase the viscosity of the solution to the desirable level. Therefore, shaping of the solution can be performed without awaiting the progress of hydrolysis of the alkoxide in the solution, and the glass can be obtained with improved uniformity of its properties. A cellulose ether is preferred as the viscosity adjusting agent, and hydroxypropyl cellulose is particularly preferable.

Abstract: A laser mirror stable at high and low temperatures is described comprising graphite fibers in a glass matrix. The mirror is made by hot pressing a graphite fiber lay-up in a glass matrix in a die having a highly polished mirror replicating surface, the fibers laid up in such a way to produce a central plane of symmetry across the central plane of the composite. In use, the composite requires a separate laser reflecting surface layer. The resulting laser mirror has a low density but no porosity, high elastic stiffness, high strength, high fracture toughness, low thermal expansion, high thermal conductivity and environmental stability.

Abstract: A method for the production of a preform with a view to obtain an optical fibre with index jump or gradient, consisting in spreading over a substrate, a solution of doped transparent substance, the said substrate being simultaneously driven in rotation about its axis and heated; the solution is spread over successive parts of the substrate, and each part starts being heated when the solution is being spread thereon.The present invention finds an application in the production of silica preforms.

Abstract: The present invention relates to the preparation of polarizing glasses from silver-containing glasses characterized by the presence of metallic silver particles therein and/or by being photochromic through the inclusion of silver halide particles therein selected from the group of AgCl, AgBr, and AgI. The method contemplates extruding the glass at a temperature between the annealing and softening points of the glass at a sufficiently high applied pressure to elongate the metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and up to 30:1 and greater. The extrudate is cooled in a manner to prevent the elongated particles from resuming their original shape. Dichroic ratios of up to 5.0 are achievable where the elongated particles exhibit an oblate configuration.

Abstract: A polycrystalline article is densified to provide either a nonporous body or a body with controlled interconnected porosity. A mixture of fine powders of the polycrystalline material and a sintering aid is compacted and outgassed under reduced pressure. The outgassed compact is then subjected to a permeation anneal step in which it is heated in a closed chamber to a temperature sufficient to form a liquid of the sintering aid, but under pressure conditions which inhibit evaporation of the sintering aid. The sintering aid can then be leached out to provide a densified article having interconnected porosity. Alternatively, the sintering aid can be leached out at elevated temperature, further densifying the compact to form a substantially nonporous body. Alternatively, the sintering aid can be removed by subjecting the densified article to an evaporation anneal step in which the article is heated to evaporate the sintering aid, further densifying the compact to form a substantially nonporous article.

Abstract: This invention relates to a process for injection molding hydrosilicate glasses and apparati useful therefor. This invention is also concerned with apparati for mixing hydrosilicate glasses while in the fluid stage, i.e., when the hydrosilicate glasses have a viscosity between about 10.sup.2 -10.sup.9 poises. Finally, this invention describes materials demonstrating ready release of hydrosilicate glasses after contact in fluid form.

Abstract: A method and apparatus is disclosed for the production of plate glass. A glass melting furnace containing molten glass connects with an outflow furnace in such fashion that central layers of molten glass in the glass melting furnace are conveyed to the outflow furnace. The outflow furnace connects with an outflow nozzle which forms a flat glass band from which the plate glass is cut. The outflow speed of the glass band issuing from the outflow nozzle is regulated by a static pressure adjustment determined by a height of the molten glass in the separate outflow furnace. A supply channel to the nozzle preferably contains heating electrodes for resistance heating of the molten glass prior to issuance from the nozzle.

Abstract: An glass manufacturing process and apparatus having a vertical air-cooled electric furnace and a transverse air-cooled refiner section. The furnace and the refiner are provided with a plurality of molybdenum plate electrode cartridge assemblies. Molten glass is removed from the furnace refiner section by means of a plurality of basin cylinders symmetrically disposed within the transverse refiner. An extruder mechanism accepts molten glass from each basin cylinder and applies the molten glass to a pair of extrusion rolls and onto a molten tin bath. The extrusion rolls are eccentrically pivoted off-center such that the separation distance between them can be varied. A cutting frame is then lowered over the tin bath such that the molten glass sheet is held firmly while it is cut into lite sizes by a cutting mechanism. After cutting, a transfer unit having suction orifices is lowered over the glass sheet and lifts the newly cut glass sheet either to an annealing stage or to a tempering stage.

Abstract: A mold assembly for making blocks of glass and constituting five parts assembled into a mold to make a mold having a cavity open at opposite ends for molding an article of glass as a sheet cut into blocks having an upstanding flange along an edge thereof and a v-shaped ridge along an opposite edge for assembly with other similar articles along a scarf joint defined by the corresponding v-shaped ridges.

Abstract: The present invention relates to an improvement in a die for extruding thermoplastic sheet having a controlled degree of microsurface roughness. The improvement comprises having a beveled leading edge on at least one of the die lips wherein the bevel is away from the die orifice in order to control the degree of microsurface roughness in the extruded sheet.