Abstract: A method of making optical waveguides is disclosed in which, to fabricate a preform, glass forming pulverulent material is filled into a mold by means of one or more screw conveyors. The quantity of glass forming pulverulent material filled into the mold per unit of time is increased by passing a suitable gas through the apparatus. Thus, the quantity conveyed per unit of time can also be controlled by adjusting the gas pressure. By using a dry gas, the moisture content of the powder can be reduced.

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: A method of molding a hollow, fiber reinforced glass matrix composite article. Reinforcing fibers are placed in a mold cavity. A billet of high temperature stable glass matrix material is heated above its flow point. The thus heated matrix materials is flowed into the mold cavity from a point inside of the article being formed and at the relative midpoint along its vertical axis. Improved article tolerance control and minimized article preform fiber disturbance is achieved.

Abstract: A sol-gel process for preparing dimensionally precise tubular silica glass articles wherein a solution having a specific gravity higher than the specific gravity of the sol solution is placed in a cylindrical container with the sol solution is provided. The container is rotated around its axis and the high specific gravity solution becomes aligned adjacent the inner wall of the cylindrical container due to the effect of centrifugal forces acting on the high specific gravity solution. The sol solution becomes aligned adjacent the inner surface of the high specific gravity solution. The tubular wet gel formed from the sol solution has a uniform thickness and a highly precise round cross-section. The dimensional precision of the wet gel is maintained by rotating the wet gel during drying in order to prevent warping.

Abstract: A silicate optical glass article is made by forming a gel from a hydrolyzed silicon alkoxide. The resulting gel is molded, cured, dried, solvents removed, heated to form a dense glass having near net shape dimensions thereby reducing expensive polishing steps to obtain the desired final dimensions and surface quality.

Abstract: The disclosed method of producing optical fiber comprises providing a silica-based glass rod of diameter D that comprises a core region of effective diameter d surrounded by cladding material (D/d typcially>2) and a silica-based porous jacketing tube, inserting the glass core rod into the porous tube, consolidating the porous material and sintering the jacketing tube onto the core rod such that a substantially pore-free optical fiber preform results. Fiber is then drawn from the preform in the conventional manner. Consolidation and sintering is carried out at a temperature below the softening temperature of the material, typically <1600.degree. C. In a preferred embodiment, the porous tube is produced by a sol/gel process that comprises mixing colloidal silica (surface area 5-100 m.sup.

Abstract: A transparent BN-type ceramic material comprising 10 to 40 wt. % of boron (B), 35 to 55 wt. % of nitrogen (N) and 3 to 40 wt. % of silicon (Si) as the main component elements, and 1 to 10 wt. % of sub-component elements, with the property of not being crystallized by heat treatment at 1600.degree. C. for one hour, and a method of producing the above ceramic material by reacting a boron-containing compound, a nitrogen-containing compound and a silicon-containing compound at deposition temperatures in a range of more than 1300.degree. C. to less than 1700.degree. C. with the total gas pressure within a reaction furnace maintained in the range from 10 Torr to 100 Torr by use of a chemical vapor deposition method are disclosed.

Abstract: A spherical silica glass powder particle having projections of network pattern on its surface is produced by gel-route formation.

Abstract: The disclosed simple, economical and rapid sol-gel process for forming a silica-based glass body, termed the "vapogel" process, comprises introduction of a silicon halide-containing gas (e.g., SiCl.sub.4 +O.sub.2) into an aqueous medium. The thus formed sol can gel within minutes, resulting in a monolithic gel from which particles having a narrow size distribution can easily be formed. The thus formed particles can be used to produce a glass body such as an optical fiber. Various techniques for forming the glass body from the gel are disclosed. Among the many advantages of the vapogel method are its ability to produce very homogeneous mixed oxide glasses of composition not obtainable by prior art sol-gel processes, and the advantageous mechanical properties of the gel produced by the method. The latter makes possible, inter alia, formation of particles having a relatively narrow size distribution.

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: This invention is directed to a method for thermal pressing a glass-impregnated preform to create a composite body with a glass or glass-ceramic matrix. The method involves contacting the preform during pressing with members prepared from a material exhibiting significant impedance to heat flow in order to delay cooling of the preform during consolidation. The preferred preform consists of a stack of glass-impregnated plies having ceramic fibers and/or whiskers entrained therein.

Abstract: A gas distributor beam includes a plenum and distribution slot surrounded by a generally V-shaped cooling fluid chamber. The circulation of a suitable cooling fluid tends to maintain the plenum and distribution slot at a temperature below four hundred degrees Fahrenheit for the distribution of diborane gas to an upper surface of a heated glass ribbon. Carbon blocks are utilized to stabilize the glass temperature above nine hundred fifty degrees Fahrenheit for the proper deposition of boron on the surface of the glass. Insulation between the carbon blocks and the outer walls of the cooling fluid chamber minimize heat transfer and the shape of the cooling chamber minimizes the exposure of the glass to the lower temperatures of the cooling chamber.

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: The invention relates to an end cap for a ceramic spool as well as to a method of and device for mounting it on the end of such a spool. The quill portion (5) of an end cap is divided by means of slits (9) into strips (10), the first ends of which are rigidly connected to a ring (12) formed by the open quill end and the other ends are rigidly connected to a flange (13) closing the other quill end, with a stub axle (6) projecting from said flange. Provided in the middle of strips (10) are threaded holes (11). The annular jacket (7) of said auxiliary device (3) can be fitted around said end cap quill (5) with a small annular clearance remaining therebetween. The annular jacket (7) is circumferentially provided with holes (17) with screws (18) extending therethrough and engageable in threaded holes (11). By turning screws (18), said strips (10) can be bent outwards so as to fit the spool end (4) inside quill (5).

Abstract: An improved method of forming an optical fiber preform includes separately forming a rod-like inner member and a hollow tube-like outer member by a soot glass deposition technique. The inner member is inserted into the outer member, while they are both in their unconsolidated state, and the asssembled parts heated to cause the outer member to collapse about the inner member and form a preform. The resulting preform can be drawn in one or more stages to provide an optical fiber having sharp step change in its index of refraction between the core and the cladding, a superior quality core to cladding interface, and improved optical transmission qualities. The inner and outer members can, if desired, be partially consolidated but for an unconsolidated layer at their interface prior to heating the outer member to cause it to join with the inner member.

Abstract: In an inside tube vapor phase deposition process for the production of doped silica glass by an oxidation reaction for optical fibre manufacture, in particular fluorine doped silica, the oxidation reaction is prevented from occurring until the reactant material, for example silicon tetrachloride and a fluorinating reagent, has been heated to a temperature above that required for the oxidation reaction. This preheating of the reactant material results in the oxidation reaction producing compositions of glasses which are not allowed from thermodynamic considerations at the lower temperature usually employed for the oxidation reaction, for example silica more highly doped with fluorine than hitherto achieved.

Abstract: Porous bodies of a material which comprises SiO.sub.2 as the main constituent are heated by passing a zone of high temperature through the body. The zone of high temperature is obtained by irradiation with light of a wavelength which is absorbed by the porous part of the body but is not absorbed by the densified part of the body (.lambda.<3 .mu.m). The device preferably comprises a rotatable radiation source (2) surrounding the body (6) to be densified.

Abstract: Apparatus for pyrolytically forming a metal compound coating on an upper face of a hot glass substrate 1 in sheet or ribbon form comprises conveyor means 2 for conveying a the substrate along a path also indicated at 1 in a downstream direction 3, a roof structure 5 defining a coating chamber 6 opening downwardly onto the path 1 and means 7 for discharging coating precursor material into the chamber 6. Upstream of the coating chamber 6 there is an antechamber 25 which communicates with the coating chamber 6 via an entry slot 24 which is defined in part by the path of the substrate 1, and via which gas can be caused to flow into the coating chamber 6 so as to form (when the apparatus is in use) a blanket layer which covers the upper face of the substrate 1 along a first part of the length of the chamber 6. Means 26 is provided for controllably preheating the gas forming the blanket layer.

Abstract: A method of manufacturing rotationally symmetrical glass bodies. The starting material for the glass body is a thixotropic suspension consisting of powered glass in a liquid dispersing agent. The suspension is introduced into a hollow mold whose geometry corresponds to that of the glass body to be formed. The hollow mold is rotated about its longitudinal axis to deposit the suspension on the inner wall of the hollow mold. The after which the green body thus formed is purified and sintered. The green body is formed by heating the rotating mold and the suspension therein to a temperature below the boiling point of the dispersing liquid until cross-linking and solidification of the starting material is obtained. Thereafter, the green body can be removed from the hollow mold.

Abstract: By hydrolyzing an organoalkoysilane monomer at high concentration in solution to form a silanol, allowing the silanol to age to produce a low molecular weight oligomer, spin-applying the oligomer onto a substrate to form a discrete film of highly associated cyclic oligomer thereon, heat treating the oligomer film to form a modified ladder-type silsesquioxane condensation polymer, and then oxidizing the silsesquioxane in an O.sub.2 RIE, an organoglass is formed which presents novel etch properties. The organoglass can be used as an etch-stop layer in a passivation process.

Abstract: A flat-bottomed quartz glass crucible for the manufacture of monocrystalline silicon is made by disposing granular quartz particles on a flat base in a cylindrical mold. A vacuum is drawn on the particles through vacuum holes in the base to retain the particles thereon while the base and mold are rotated, and while the particles are heated to fuse them into a quartz glass crucible shape.

Abstract: Incorporation of fluorine into a porous silica body, such as an unsintered body produced by a sol-gel method, by VAD or OVPO, reduces or eliminates bubble or pore formation upon re-heating of the glass formed by sintering of the porous material. Effective fluorine concentrations are between 0.01 and 5% by weight. The invention can be used advantageously in producing preforms and optical fiber.

Abstract: A machine for making and painting test tubes by painting open-ended tubes and then fusing and severing them to form individual test tubes.Substitutable paint applicators varying in width, adjustable in location relative to the open-ended tubes, apply paint thereto by means of wiping action caused by rotating said open-ended tubes while in engagement with said paint applicators. The open-ended tubes are then individually fused and severed intermediate their open ends to form, from each open-ended tube, two separate test tubes having painted bands of the desired width and at the desired location, including painted bands which are contiguous with the open ends of the test tubes.

Abstract: A method of and arrangements for manufacturing glass bodies, in which the starting material for the glass body, being an anhydrous suspension having a microdispersed solids content, is used to form a porous green body which is subsequently purified and sintered, in which by separating the phases of an anhydrous suspension the green body is formed by means of electrophoresis on a deposition electrode whose shape corresponds to that of the glass body to be produced.

Abstract: Method and equipment for the manufacture of glass bodies with which a porous green body is formed from the starting material for the glass body in the form of an aqueous suspension with highly disperse solids content and this green body is then purified and sintered, the green body being deposited by separation of the phases of the suspension by electrophoresis.

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: Method and equipment for the manufacture of glass bodies wherein a porous green body is formed by extrusion from the starting material for the glass body in the form of a thixotropic suspension and this green body is then purified and sintered, during which process the starting material is brought in a state of minimum viscosity into an extruding press closed at its outlet end, is heated in the extruding press to a temperature below the boiling point of the dispersing liquid and then, after the extruding press is opened, is extruded into a green body of dimensionally stable shape by means of the die of the extruding press.

Abstract: A method of manufacturing glass bodies, in which the starting material for the glass body, in the form of microdispersed SiO.sub.2 particles, is used to form an open-pore green body which is subjected to a cyclic purification process in which the impurities present in the green body react with a purifying gas which is heated to a temperature in the range from 600.degree. to 900.degree. C., after which the green body is sintered; in each cycle of the said process, the arrangement holding the green body to be purified being flushed and subsequently evacuated.

Abstract: A process for forming monolithic silica glass articles is provided. The process includes the steps of hydrolyzing silicon alkoxide to form a hydrolyzed solution, adding fumed silica to the hydrolyzed silicon alkoxide solution to yield a sol solution, gelling the sol solution to a gel, and drying and sintering the gel to obtain the monolithic silica glass articles.

Abstract: A sol-gel method of preparing doped glass articles is provided. The glass is formed by preparing a sol solution containing hydrolyzed silicon alkoxide and ultrafine particle silica. The sol solution can also include a dopant. The sol solution is gelled in a container, dried and sintered to yield the doped silica glass articles.

Abstract: A method of preparing preforms for optical fibers is provided. The method includes preparation of a first sol solution of a silicon alkoxide hydrolyzed with an acid and ultrafine particle silica, placement of the first sol solution into a container, and gelation of the first sol solution while the container is being rotated to yield a wet gel having a center hole. A second sol solution having a different composition than the first sol solution is prepared and used to fill the center hole in the wet gel. The second sol solution is then gelled to a wet gel composite and the composite is dried and sintered to yield the preform.

Abstract: A silicate optical glass article is made by forming a gel from a hydrolyzed silicon alkoxide. The resulting gel is molded, cured, dried, solvents removed, heated to form a dense glass having near net shape dimensions thereby reducing expensive polishing steps to obtain the desired final dimensions and surface quality.

Abstract: A powdery substance, such as for example pyrogenically prepared silicon dioxide, is subjected to predensification through the utilization of centrifugal force in a centrifuge. Subsequently, the centrifuge receptacles are closed with a free flying piston. Through utilization of the centrifugal force, there is achieved through the use of the free flying piston an additional pressure which is exerted on the predetermined powdery substance.

Abstract: A method of preparing tubular silica glass is disclosed. The method includes the steps of first hydrolyzing silicon alkoxide with acid and then adding ultra-fine particle silica to form a sol solution. The sol solution is placed in a cylindrical container and gelled while rotating the cylindrical container to obtain a tubular gel. The tubular gel is dried and sintered to the tubular silica glass.

Abstract: A coating hood for applying protective coatings to glass containers, includes a pair of spaced side walls; a supply of vaporized or atomized coating chemical in a carrier gas; a conveyor for transporting the glass containers to be coated longitudinally through the coating hood; a hood ceiling with a plurality of openings positioned at the level of the container finishes for supplying coating free air across the finish of the containers; the openings on one side of the containers are offset in the longitudinal direction of the hood with respect to the openings on the other side of the containers; each opening supplying an envelope of the coating free air across the finish of the containers such that lateral boundaries of the envelope of each opening on one side of the containers are substantially coincident with lateral boundaries of the envelopes of the offset and laterally adjacent openings on the other side of the containers; and a blower for supplying the coating free air to the openings.

Abstract: A process is provided for treating an aqueous stream of nonradioactive hazardous waste containing inorganic compounds capable of forming oxides upon thermal treatment in which at least one of the oxides is a glass former, glass intermediate or a glass modifier. The process comprises (a) introducing the waste stream into a thermal treatment zone; (b) heating the inorganic compounds in the thermal treatment zone to convert the compounds to the corresponding inorganic oxides and form a melt solution while vaporizing volatile components to form an off-gas; (c) scrubbing the off-gas to provide a ventable flue gas and a liquid condensate with the condensate being recycled to the thermal treatment zone; and (d) removing the melt solution from said thermal treatment zone and cooling the melt solution to form a nonleachable glass containing the hazardous waste. An apparatus particularly adapted to practice the process is also provided.

Abstract: A method of making fiber reinforced glass composite articles utilizes preregnated preforms which are bound with a temporary plastic binder. The binder is removed in a gradient oven and the frit or preform is drawn through a pultrusion die assembly heated to the degree necessary to render the frit workable. Deformation in the heated die assembly is maintained during cooling, resulting in a formed glass composite article.

Abstract: For fabricating porous bodies from a glass starting material, particularly in connection with the fabrication of an optical waveguide preform, it is proposed to fill powdery glass starting material under a pre-compaction into a compression mold, and to compress it thereafter. When the porous body to be formed is to have a varying composition in the radial direction, as is necessary with a view to step index optical fibers or optical waveguides having a graded index of the refractive-index profile, then differently composed powdery glass starting materials are filled one at a time, in adjacent coaxial areas, into the compression mold. This is effected with respect to each of the individual areas with the aid of a screw conveyor under a continuous, adjustable pressure and at an adjustable conveying speed.

Abstract: A method for producing sodium-containing glasses, by a vapor deposition process wherein a vapor mixture containing a sodium fluoroalkoxide compound is reacted to provide a particulate sodium-containing vapor deposition product which can be sintered to a glass.

Abstract: Apparatus for coating glass by pyrolysis of a powder at the glass surface to form a coating on that surface, and in which a flow of a suspension of a powder in a carrier gas is applied to a moving hot glass surface across the width of that surface, comprising means for supporting and advancing hot glass beneath an applicator comprising a chamber terminating in a slot extending across the supporting means close to the path of the glass surface to be coated, which chamber diverges downwardly from a central inlet for the downward flow of the suspension of the powder.

Abstract: In the manufacture of a quartz glass crucible of low bubble content, a first layer of granular quartz material is disposed on the interior of a rotating mold through the walls of which a vacuum can be drawn. A second layer of finer quartz material is then disposed on the first layer. The quartz material is then heated, melted and fused to form a crucible.

Abstract: The instant invention is directed to the production of boards and other relatively thick-walled shapes of various configurations from inorganic silicates. The method for preparing such products involves five general steps: first a fully or predominantly crystalline body is formed containing crystals consisting essentially of a lithium and/or sodium water-swelling mica selected from the group of fluorhectorite, boron fluorphlogopite, and solid solutions therebetween; second, that body is contacted with a polar liquid, customarily water, to cause swelling and disintegration of the body accompanied with the formation of a gel; third, the gel is contacted with a source of large cations to effect an ion exchange reaction between the large cations and the Li.sup.+ and/or Na.sup.

Abstract: A method for preparing high quality silica glass articles is provided. The glass is prepared by hydrolyzing silicon alkoxide with a basic reagent to yield a first solution, hydrolyzing a silicon alkoxide with an acid reagent to yield a second solution, mixing the first solution with the second solution at a predetermined mixing rate to yield a sol solution, pouring the sol solution into a container, gelling the sol solution to a wet gel, drying the wet gel to a dry gel, and sintering the dry gel to yield a silica glass.

Abstract: In order to facilitate a shape-keeping compression in a process of fabricating an elongated glass-body, particularly a preform for optical waveguides on the basis of SiO.sub.2 in which, from a powdery glass starting material a porous body is formed and sintered into a glass body, there is provided a process in which the filling of the powdery glass starting material into the compression mold is carried out by simultaneously effecting a precompaction and in which, following the fill-in operation, the pre-compacted powdery material is compressed to obtain the porous body. Steps and measures are proposed for stabilizing the flexible hose which is preferably used as a compression mold, in its shape during the fill-in process. For the filling-in of the material there is used a screw conveyor or an arrangement of several screw conveyors arranged coaxially or next to each other, in order to form a porous body having the desired radial material composition.

Abstract: A method for continuously melting a glass by means of a high-frequency electromagnetic field in a melting tube is provided. In this technique, the electromagnetic field is coupled in the melt by means of a coil present within a cooling jacket surrounding the melting tube. A grounded screen and a tube of insulating material are present between the wall of the melting tube and the coil. The melt traverses a heating zone and a refining zone, and a solid elongated body is withdrawn from the bottom of the melting tube.

Abstract: Freestanding glass reinforced ceramic protective coatings are made with a shrinkable silica preform technique. The coatings may be bonded to heat sensitive organic (plastic) or inorganic (ceramic or metal) substrates to provide thermal and impact protection.

Abstract: This invention relates to an apparatus for preparing samples. These samples will be used for making disks and solutions for subsequent analysis by chemical or physical means. The machine contains an assembly of several gas burners with a crucible above each of them for heating and melting the sample-flux mixture. Efficient mixing in the melt is obtained by providing a crucible with a new shape in combination with a periodic tilting or rotation of the crucible. Solutions are prepared by pouring the hot molten glass mixture into beakers containing an acid and by agitating the acid and the glass particles. Glass disks are prepared by placing moulds above the crucibles during heating and by turning the crucibles and the moulds upside down so that the hot molten glass mixture flows into the moulds for subsequent solidification into solid glass disks of high quality, ready for analysis without further processing. Various shapes of crucibles are disclosed.

Abstract: High silica glass is formed by sintering a dried gel. The gel has a pore size distribution such that at most about 5% of the total pore volume is contributed by pores having an effective pore diameter greater than about 0.5 .mu.m, and such that at least 10% of the total pore volume is contributed by pores having an effective pore diameter greater than about 0.02 .mu.m. This pore size distribution permits effective migration of fluid into, and out of, the gel, permits sintering at a lower temperature, and results in increased perfection of the glass. The pore size distribution can be achieved by appropriate comminution, e.g., ball-milling, of intermediate material. A novel process for forming high silica glass is also disclosed. The process comprises forming intermediate material by hydrolysis of one or more metal alkoxides, comminuting the intermediate material to produce colloidal particles, forming a sol by dispersing the particles in liquid, gelling the sol, drying the gel, and sintering the dried gel.

Abstract: A green compact (17) preheated to a predetermined temperature in a heating furnace (16) is inserted into a container comprising a press table (20) and a hollow cylinder (25), and molten glass (33) is then placed into the container. The green compact (17) is uniformly pressed by a press rod (29) through the molten glass (33). The molten glass (33) is cooled by a coolant flowing through channels (22) and (26) formed in the press table (20) and the cylinder (25), whereby a solidified shell (34) is formed at the outer peripheral portion of the mass of glass. Finally, the shell (34) is taken out from the container, and the molten portion of glass (33) is transferred into a ladle (31) through a grating (30), leaving the compressed sintered product on the grating (30).