Abstract: To inhibit, or at least sharply attenuate, fluorescence of a quartz-glass velope (10) surrounding a light source (11), such as a halogen incandescent lamp, a high-pressure discharge lamp, or the like, when the quartz glass is subjected to ultraviolet (UV) radiation from the light source, and has been doped with a UV radiation absorbing material, typically a cerium, or cerium-titanium doping, the quartz-glass envelope is additionally doped with praseodymium or a praseodymium compound, such as praseodymium oxide or praseodymium aluminate. The pure praseodymium in the doping is, preferably, present in quantities of between about 0.008 and 1.25%, by weight, with reference to the undoped quartz glass. Barium metaborate can also be used, preferably together with praseodymium to attenuate the fluorescence.

Abstract: The high-purity, opaque quartz glass containing 3.times.10.sup.6 -9.times.10.sup.6 of closed cells having an average size of 20-40 .mu.m per 1 cm.sup.3, a ratio of closed cells having sizes of 100 .mu.m or more to the whole of cells being 1% or less, thereby showing 5% or less of linear transmittance for near infrared rays (.lambda.=900 nm) at a thickness of 1 mm is produced by compacting amorphous silica powder having an average particle size of 0.5-10 .mu.m, in which each of impurities selected from Li, Na, K, Fe, Ti and Al is 1 ppm or less, if any, and sintering the resultant green body at 1730.degree.-1850.degree. C.

Abstract: A fine silica tube composed of silica gel and having an outer diameter of 0.05 to 2 .mu.m wherein the cylindrical wall portion of the tube has a cross-section defined by a substantially square outer periphery and a substantially square vacant center, or by a circular outer periphery and a substantially square vacant center; and a fine silica tube composed of silica glass and having an outer diameter of 0.05 to 1.4 .mu.m wherein the cylindrical wall portion of the tube has a cross-section defined by a substantially square outer periphery and a substantially square vacant center. The fine silica gel tube is made by treating a tetraalkoxysilane with ammonia or aqueous ammonia in a water-soluble alcohol medium in the presence of tartaric acid, citric acid, a tartaric acid salt or a citric acid salt, whereby the tetraalkoxysilane is hydrolyzed. The fine silica glass tube is made by calcining the fine silica gel tube at 800.degree. to 1,400.degree. C.

Abstract: Soft quartz glass having low viscosity and a low thermal coefficient of expansion, high electrical insulation capability and free from release of contaminants, when used as a bulb of an incandescent lamp or as an envelope in an arc vessel of a discharge lamp, is a quartz glass made of ultra-pure quartz (SiO.sub.2), for example having a purity of 99.99 mol-%, doped with stoichiometric compounds of alkaline earth oxides with boron oxide, optionally also with a small quantity of Al.sub.2 O.sub.3 in an overall quantity of the doping substance of between about 0.05% to 0.8%, by weight.

Abstract: A synthetic quartz glass optical member for an ultraviolet laser, where the quartz glass has a hydroxyl content of 10-100 ppm, a chlorine content of 200 ppm or less, a hydrogen content of 1.times.10.sup.16 molecules/cm.sup.3 or less, a homogeneity of refractive index of 5.times.10.sup.-6 or less in terms of .DELTA.n, and a birefringence of 5 nm/cm or less.

Abstract: An improved fiber reinforced glass composite includes a carbon-coated refractory fiber in a matrix of a black glass ceramic having the empirical formula SiCxOy where x ranges from about 0.5 to about 2.0, preferably 0.9 to 1.6 and y ranges from about 0.5 to 3.0, preferably 0.7 to 1.8. Preferably the black glass ceramic is derived from cyclosiloxane monomers containing a vinyl group attached to silicon and/or a hydride-silicon group.

Abstract: An improved fiber reinforced glass composite includes refractory fiber in a matrix of a black glass ceramic having the empirical formula SiCxOy where x ranges from about 0.5 to about 2.0, preferably 0.9 to 1.6 and y ranges from about 0.5 to 3.0, preferably 0.7 to 1.8. Preferably the black glass ceramic is derived from cyclosiloxane monomers containing a vinyl group attached to silicon and/or a hydride-silicon group.

Abstract: A dielectric barrier discharge lamp has a discharge vessel having a discharge chamber filled with a discharge gas. Excimer molecules are developed due to a dielectric barrier discharge. The discharge vessel is equipped with a window for the output of the light radiated from the excimer molecules. A getter space, equipped with a getter, communicates with the discharge chamber. A common wall separates the discharge chamber from the getter space, or a separately arranged getter space is connected to the discharge chamber via a tube. In one form, the discharge vessel and window is made of quartz glass containing less than 10 ppm of OH radicals by weight.

Abstract: The present invention relates to a heat resistant composition which exhibits excellent heat and wear resistances after being cured. Further, it has excellent releaseability and durability, and the cured film thereof has a more excellent stability than a prior art adhesive of this type, by preparing it from two components: a powder mixture consisting of 20% by weight or more of zirconium oxide, 1 to 10% by weight of sodium titanate, 2 to 15% by weight of yttria based on the zirconium oxide and the balance of silica; and a sodium silicate containing a small amount of water added thereto.

Abstract: A synthetic quartz glass optical member for an ultraviolet laser, suitably applicable as a stepper lens of a lithographer using an excimer laser beam and other optical members, wherein the quartz glass has a hydroxyl content of 10 to 100 ppm, a chlorine content of 200 ppm or less, a hydrogen content of 1.times.10.sup.16 molecules/cm.sup.3 or less, a homogeneity of refractive index of 5.times.10.sup.-6 or less in terms of .DELTA.n, and a birefringence of 5 nm/cm or less. The optical member can be produced by subjecting a volatile silicon compound to flame hydrolysis with oxyhydrogen flame, depositing the formed particulate silica on a heat-resistant support to prepare a porous silica matrix, heating the matrix in a vacuum as high as 1.times.10.sup.-2 Torr or above to a temperature of 1,400 .degree. C.

Abstract: A synthetic quartz glass substrate (1) supporting active elements is formed of high-purity synthetic quartz glass having, a hydroxyl group content of 200 ppm or below and chlorine group content of 50 ppm or below. The substrate (1) may have an impurity level of 1 ppm or less sodium and 1 ppm or less aluminum. TFTs (6), i.e., active elements, and picture element electrodes (7) are formed on the surface of the synthetic quartz glass substrate (1) to construct a driving panel for a liquid crystal display of an active matrix type. A liquid crystal panel is formed by disposing the driving panel and a counter substrate (2) opposite to each other and sandwiching a liquid crystal layer (3) between the driving panel and the counter substrate (2).

Abstract: A silica glass optical fiber superior in resistance to ultraviolet rays, which fiber comprises a doped silica glass cladding layer formed on a silica glass core, said silica glass core having an OH content of 10-1000 ppm, a fluorine content of 50-5000 ppm, and being substantially free of chlorine.

Abstract: A quartz glass substrate for polysilicon thin film transistor liquid crystal display, in which a halogen content is not more than 10 ppm; an OH content is not more than 100 ppm; a total content of a heavy metal element and an alkali metal element is not more than 1 ppm; and an annealing point is not less than 1,150.degree. C.

Abstract: Quartz glass obtained by flame-hydrolyzing a glass-forming raw material to obtain fine particles of quartz glass, having the fine particles of quartz glass deposited and grown on a substrate to obtain a porous quartz glass product and heating the porous quartz glass product to obtain a transparent quartz glass product, which has an OH content of not more than 10 ppm and a halogen content of at least 400 ppm and which contains hydrogen.

Abstract: The present invention relates to a process for making glass by the sol-gel process. A mixture of silicon alkoxide, at least two other metal alkoxides, and alcohol in a solution sufficiently acidic to hydrolyze partially the silicon alkoxide is formed. Water is then added under agitation to convert the metal alkoxides to a network of corresponding metal oxides suitable for gelation. The mixture containing the network of metal oxides is then molded for a sufficient time to form a gel. Substantially only oxides of one of the at least two other metals is then removed from the gel, which is then fixed in a liquid capable of arresting such additional removal. The fixed gel is then dried and sintered to form a glass. The step of removing the at least one other metal oxide from the gel can be followed with a step of withdrawing partially oxides of one of the remaining at least two other metals in order to form a transparent gradient-index glass after sintering.

Abstract: A synthetic silica glass article made by hydrolyzing an alkoxysilane and thermally sintering the resulting silica; this synthetic silica glass article has a viscosity of not lower than 10.sup.10 poise at 1400.degree. C., and contains, as metallic impurities, less than 1 ppm of Al, less than 0.2 ppm of Fe, less than 0.2 ppm of Na, less than 0.2 ppm of K, less than 0.01 ppm of Li, less than 0.2 ppm of Ca, less than 0.02 ppm of Ti, less than 0.01 ppm of B, less than 0.01 ppm of P, less than 0.01 ppm of As.

Abstract: A yellow color by transmitted light is produced in a high silica glass by impregnating a porous, high silica glass with a solution of chromium and zinc salts and consolidating the glass under oxidizing conditions to dope the glass with chromium and zinc oxides, the chromium being predominantly in the hexavalent state. Optionally, an aluminum salt is included in the impregnating solution. The glass has particular utility as a filter for lighting purposes.

Abstract: The present invention relates to a process for making glass by a sol-gel process. The process is initiated by forming a mixture of silicon alkoxide and an alcohol in a solution sufficiently acidic to partially hydrolyze the silicon alkoxide. An index modifying metal alkoxide selected from the group consisting of alkoxides of titanium and zirconium is then added to the mixture. Water is next added to convert the metal alkoxides to a network of corresponding metal oxides suitable for gelation. The mixture containing the network of metal oxides is then contained for sufficient time to form a gel. The gel is acid leached for enough time to remove some of the index modifying metal oxide. To prevent further removal of index modifying metal oxide from the gel, the gel is fixed. The fixed gel is then rinsed with a solvent to remove precipitates from the gel, dried, and sintered into a transparent gradient-index glass.

Abstract: Rare earth element doped silica glass according to the invention is prepared by doping silica-based glass co-doped with a rare earth element and aluminum additionally with fluorine and has excellent physical properties including remarkable light emission characteristics and an excellent capability of being fused with other silica-based glass. Such doped silica glass provides high amplification gains and a wide wavelength bandwidth and therefore can be used as a material for manufacturing miniaturized optical devices. Particularly, since the manufacturing process adapted to produce rare earth element doped silica glass according to the invention does not involve crystallization that normally characterizes the type of doped silica glass under consideration, the obtained doped silica glass is transparent and totally free from air bubbles.

Abstract: A yellow color by transmitted light is produced in a high silica glass by impregnating a porous, high silica glass with a solution of chromium and zinc salts and consolidating the glass under oxidizing conditions to dope the glass with chromium and zinc oxides, the chromium being predominantly in the hexavalent state. Optionally, an aluminum salt is included in the impregnating solution. The glass has particular utility as a filter for lighting purposes.

Abstract: Highly heat resistant glass fiber which comprises from 0.1 to 2.0 wt % of Al.sub.2 O.sub.3, from 0.1 to 2.0 wt % of TiO.sub.2, from 96 to 99.8 wt % of SiO.sub.2 and not more than 0.03 wt % of the sum of alkali metal oxides and alkaline earth metal oxides.

Abstract: Carbon-containing black glass compositions of matter having the empirical formula SiC.sub.x O.sub.y in which x ranges from about 0.5 to about 2.0, and y ranges from about 0.5 to about 3.0, wherein the carbon content of the black glass ranges from about 10% to 40% by weight, are prepared by pyrolysis of a cyclosiloxane polymer in a non-oxidizing atmosphere at a temperature from about 750.degree. C. to about 1400.degree. C.

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 body of cerium-doped quartz glass is manufactured by melting together silicon oxide and a cerium (III) silicate compound, preferably Ce.sub.2 Si.sub.2 O.sub.7, in a reducing atmosphere. The invention provides a method of manufacturing said cerium-silicate compound having a tetragonal crystal structure. The quartz glass manufactured can be suitably used in a lamp envelope of UV-absorbing quartz glass, the water content in the quartz glass being less than 1 ppm.

Abstract: The high-purity, heat-resistant oxynitride glass can be produced by subjecting a fine silica powder block to a nitriding treatment by heating it while keeping it in contact with an ammonia-containing gas in a reducing environment, which is achieved by at least one of the following means: (a) embedding the fine silica powder block in carbon powder, (b) placing the fine silica powder block in a carbon pipe or container, and (c) introducing a reducing gas, and simultaneously or subsequently sintering it.

Abstract: A process for forming a high temperature oxidation resistant coating on a carbon-carbon composite is disclosed and claimed. The process comprises applying a cyclosiloxane monomer blend containing a filler such as silicon carbide to a carbon-carbon composite, polymerizing and pyrolyzing said blend to form a filled black glass protective coating on the carbon-carbon composite.

Abstract: A gradient index glass comprised of (SiO.sub.2).sub.m (R.sub.2 O).sub.n X.sub.p, wherein R is Li, Na, K, Rb, or Cs, and X=TiO.sub.2, ZrO.sub.2 and/or HfO.sub.2, m is 44 to 99, n is 0.25 to 20, p is at least 0.1, and m+n+p=100.

Abstract: A method for producing a nonsintered cristobalite particles comprising heating amorphous silica particles at a temperature of 1400.degree. to 1700.degree. C. in the presence of cristobalite particles (hereinafter referred to as cristobalite particles for addition and mixing) of at least 5 parts by weight based on 100 parts by weight of said amorphous silica particles to convert said amorphous silica particles to cristobalite particles with their particle form kept unchanged. According to the present invention, dense cristobalite having a low alkali content can be obtained in the form of particles. Such cristobalite is used as a filler, a dispersing agent, etc., and also as a material for high-quality artificial quartz, ceramics, etc., and particularly as a material for transparent quartz glass because of its generating no bubbles at the time of melt-molding.

Abstract: A synthetic silica glass article made by hydrolyzing an alkoxysilane and thermally sintering the resulting silica; this synthetic silica glass article has a viscosity of not lower than 10.sup.10 poise at 140.degree. C., and contains, as metallic impurities, less than 1 ppm at Al, less than 0.2 ppm of Fe, less than 0.2 ppm of Na, less than 0.2 ppm of K, less than 0.01 ppm of Li, less than 0.2 ppm of Ca, less than 0.02 ppm of Ti, less than 0.01 ppm of B, less than 0.01 of P, less than 0.01 ppm of As.

Abstract: A process for producing a ceramic preform, which comprises mixing an alkoxysilane and fine silica powder, molding the mixture, followed by heating for de-alcoholysis.

Abstract: Porous glass consisting essentially of silica, zirconia and an alkali metal compound, wherein the content of zirconia is at least 5% by weight and the content of the alkali metal compound is at least 2% by weight as calculated as M.sub.2 O wherein M is an alkali metal element, and the total pore volume (A) of pores having pore radii of from 20 to 10,000 .ANG. is at least 0.2 ml/g, and the proportion of the pore volume (B) of pores having pore radii of from 100 to 10,000 .ANG. to the total pore volume (A) of pores having pore radii of from 210 to 10,000 .ANG. is at least 80%.

Abstract: A crystalline composition having an X-ray diffraction pattern essentially the same as the high cristobalite form of silica comprising SiO.sub.2, Al.sub.2 O.sub.3 and a metal oxide (Me.sub.x O) in which Me is selected from Na, Ca, Sr and mixtures thereof.

Abstract: A semiconductor-containing glass having a high nonlinear optical effect is provided which comprises a glass matrix mainly composed of SiO.sub.2 wherein said glass matrix contains a semiconductor microcrystal having a particle size of less than 100.ANG..This semiconductor-containing glass is produced by a method which comprises subjecting a solution containing a metal alkoxide containing at least a silicon alkoxide as well as a semiconductor having a particle size of less than 100.ANG., to hydrolysis reaction to obtain a gelled solid and heating the resulting gelled solid to 400.degree.-1300.degree. C. to form a glass or a method which comprises subjecting a solution containing a metal alkoxide containing at least a silicon alkoxide as well as a metal salt which becomes semiconductor upon decomposition, to hydrolysis reaction to obtain a gelled solid; heating the gelled solid to 400.degree.-1300.degree. C. to form a glass; and simultaneously with or after the heating to 400.degree.-1300.degree. C.

Abstract: A porous body of fibrous, low density silica-based insulation material is at least in part impregnated with a reactive boron oxide containing borosilicate glass frit, a silicon tetraboride fluxing agent and a molybdenum silicide emittance agent. The glass frit, fluxing agent and emittance agent are separately milled to reduce their particle size, then mixed together to produce a slurry in ethanol. The slurry is then applied to the insulation material and sintered to produce the porous body.

Abstract: A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2. The composition is formed from a mixture of finely divided particles of 25-50 vol. % borosilicate glass and 50-75 vol. % high silica glass. The borosilicate glass comprises approximately 20-35 wt. % B.sub.2 O.sub.3 and approximately 60-80 wt. % SiO.sub.2. The high silica glass contains essentially 0.5-1 wt. % alumina, 1-5 wt. % B.sub.2 O.sub.3 and approximately 95-98 wt. % SiO.sub.2. The composition can be fired at a temperature of less than 1000.degree. C.

Abstract: Gradient-index glass is produced in a sol-gel process by utilizing water or a mixture of water and alcohol. This technique is particularly suitable for production of glass bodies with a ternary system of metal alkoxides, including silicon alkoxide, an index modifying metal alkoxide, such as alkoxides of titanium and zirconium, and an additional metal alkoxide, such as an alkoxide of aluminum, boron, or germanium.

Abstract: A surface conductive paste composition to be applied to the surface of a green sheet for a cermaic substrate or to the surface of a ceramic substrate after being fired and to be then fired, the solid content of which has a composition comprising from 80 to 99.9% by weight of Au powder, from 0.1 to 20% by weight of crystallized glass frit and from 0 to 19.9% by weight of non-crystallized glas frit, provided that the total of the crystallized glass frit and the non-crystallized glass frit is at most 20% by weight, and which has a lead compound powder incorporated in an amount of from 0 to 5% by weight based on the total amount of said composition.

Abstract: A process for making non-porous, dense, silica partices having a diameter of about 3 to 1000 microns, a nitrogen B.E.T. surface area less than about 1 m.sup.2 /g, a total impurity content of less than about 50 ppm and a metal impurity content content of less than about 15 ppm from an aqueous dispersion of fumed silica. The particles are converted into porous particles and sintered in an atmosphere having a water partial pressure of from about 0.2 to about 0.8 atmosphere for temperatures below about 1200.degree. C.

Abstract: The invention provides a synthetic silica glass article or tool for a dopant-diffusing process in semiconductors, which is quite satisfactory in use in respect of the outstandingly small creeping at high temperatures, by working from a silica glass block having such a creeping characteristic that the elongation under a tension of 62.5 g/mm.sup.2 at a temperature of 1250.degree. C. does not exceed 0.025% after 5 minutes.

Abstract: This invention is directed to a process of producing semiconductor devices which involves deposition of protective glass layers by a particle beam technique from targets of phosphosilicate glass, as well as a process for production of such targets. The phosphosilicate glass containing 1-15 mole percent P.sub.2 O.sub.5 is produced by a sol/gel technique which involves mixing of a fumed silica, with a surface area of 50-400 m.sup.2 /g, preferably about 200 m.sup.2 /g, with phosphoric acid and water to form a sol with 20-55 wt. % silica, allowing it to gel, drying at ambient conditions, dehydrating at about 650.degree. C. in an atmosphere of an inert gas and chlorine and fluorine containing gases, heating up at a certain rate of from 100.degree. to 180.degree. C. per hour to a peak sintering temperature below 1200.degree. C. and cooling so as to produce amorphous and transparent glass suitable for use as a target. The glass layers are highly advantageous as encapsulating layers, diffusion barrier layers, etc.

Abstract: Porous glass consisting essentially of silica, zicronia and an alkali metal compound, wherein the content of zirconia is at least 5% by weight and the content of the alkali metal compound is at least 2% by weight as calculated as M.sub.2 O wherein M is an alkali metal element, and the total pore volume (A) of pores having pore radii of from 20 to 10,000 .ANG. is at least 0.2 ml/g. and the proportion of the pore volume (B) of pores having pore radii of from 100 to 10,000 .ANG. to the total pore volume (A) of pores having pore radii of from 20 to 10,000 .ANG. is at least 80%.

Abstract: An inorganic glass having high water repellence produced by irradiating and/or implanting ions upon or into a surface of the inorganic glass, the ions are those of at least one element selected from the group consisting of(a) halogen elements selected from F, Cl, and Br, group 3A, 3B, 4A and 5B elements of the International Periodic Table selected from Al, Ti, Y, In and Bi,(b) rare gas elements selected from He, Ne, Ar, Kr and Xe, group 3A, 4A, 1B, 2B, 3B, 4B and 5B elements of the International Periodic Table selected from Sc, Cu, Zn, Ag, Cd, Sn, Sb, Au, Hg, Tl and Pb, alkali metal or alkaline earth metal elements selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba, and(c) Ce, the dose of th (a), (b) and (c) ions being 5.times.10.sup.14 to 1.times.10.sup.20 ion/cm.sup.2, 5.times.10.sup.14 to 1.times.10.sup.17 ion/cm.sup.2 and 1.times.10.sup.17 to 1.times.10.sup.20 ion/cm.sup.2, respectively.

Abstract: A silica glass excellent in optical properties can be produced by a sol-gel process without generating cracks and fractures by adding to a hydrolysis system at least before gelation (A) an organic polymer such as a polyalkylene glycol, etc. and/or (B) an organic solvent such as N,N-dimethylacetamide, etc.

Abstract: Porous, silica-rich shapes have improved strength and abrasion resistance by leaching the precursor glass shape in preconditioned acid having silica ion and at least one common ion that is also present in the precursor glass shape. The precursor glass shapes have shapes such as fibers, hollow fibers, tubes, rods, beads, hollow spheres and plates and compositions having 30-75 volume percent silica and at least 10-65 volume percent nonsiliceous acid extractable components. Preconditioning of the acid solution results from a pretreatment of the acid with compounds that dissociate into the ions when added to the acid solution or with shapes, particles or fragments of glass compositions different from or similar to the glass shape to be leached so long as the glass composition has extractable material to provide the silica ion and at least one common ion.

Abstract: A process for the production of a glass by the vacuum melting method using silica as a raw material is disclosed, comprising filing a silica fine powder in a suitable vessel, heating it in the presence of an accelerator for phase conversion to obtain a porous formed body consisting of a cristobalite phase, and then heating and melting the formed body in vacuo. According to the present invention, a transparent and active glass having a high quality can be produced at an inexpensive cost.

Abstract: A complex-shaped bonded body of silicon nitride having a high bonding strength of more than 30 kg/mm.sup.2 as flexural strength and continuously homogenous microstructure through the bonded portion can be obtained by the method comprising the following five steps:(a) molding a body from a mixture of silicon powder having a diameter of less than 44 .mu.m and non-oxide ceramics powder having a diameter of less than 44 .mu.m,(b) heating a molded body obtained by step (a) at a temperature of 600 to 1500.degree. C. in a non-oxide atmosphere such as nitrogen or argon gas to sinter said silicon powder and partially convert to silicon nitride retaining 60 to 100 wt. % unreacted silicon powder therein,(c) grinding a surface to be bonded together with other bodies of said presintered body obtained by step (b) to dispose of unreacted silicon thereon,(d) placing a bonding agent containing silicon powder having a diameter of less than 44 .mu.

Abstract: Method of preparing an aluminum oxide containing quartz glass activated by bivalent europium and comprising as glass matrix oxides mainly SiO.sub.2 and furthermore per mol of SiO.sub.2 up to at most 0.15 mol of at least one of the oxides, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, P.sub.2 O.sub.5, ZrO.sub.2, Scf.sub.2 O.sub.3, Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Gd.sub.2 O.sub.3, Lu.sub.2 O.sub.3, the alkali metal oxides and the alkaline earth metal oxides. A mixture is made of the composite oxides or of compounds which yield these oxides. The mixture comprises europium in the form of an aluminum containing compound of bivalent europium. The mixture is melted at a high temperature in a reducing atmosphere and is then cooled. The luminescent quartz glasses obtained are used in luminescent screens of, for example, low-pressure mercury vapor discharge lamps.

Abstract: Luminescent quartz glass comprising as a glass matrix oxide mainly SiO.sub.2 and furthermore per mole of SiO.sub.2 from 0 to 0.15 mol of at least one of the oxides Al.sub.2 O.sub.3, B.sub.2 O.sub.3, P.sub.2 O.sub.5, ZrO.sub.2, Sc.sub.2 O.sub.3, Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Gd.sub.2 O.sub.3, Lu.sub.2 O.sub.3, the alkali metal oxides and the alkaline earth metal oxides. The glass comprises as an activator oxide at least one of the oxides Tb.sub.2 O.sub.3 and Ce.sub.2 O.sub.3 in a quantity of 0.75 to 15 mol % calculated with respect to the glass matrix oxides. In one embodiment the glass comprises Tb.sub.2 O.sub.3 and also not more than 0.2 mol % of Eu.sub.2 O.sub.3 as an activator oxide. The glasses are preferably obtained by a sol-gel technique and are useful, for example, in luminescent screen of low-pressure mercury vapor discharge lamps.

Abstract: A sol-gel method for making gradient-index glass and a novel composition therefor, comprising at least a ternary system of metal alkoxides.

Abstract: A method for the manufacture of silicon layers containing boron and phosphorus dopants wherein the silicon wafers are positioned in a reaction chamber into which there is introduced, from separate sources, (a) tetraethylorthosilicate as a source of silicon dioxide, (b) trimethylborate as a source of boron, and (c) a phosphorus source. The three reactants are decomposed in the reaction chamber to deposit silicon dioxide doped with boron and phosphorus onto the wafers, the decomposition being carried out at a temperature of at least 600.degree. C. and at a substantially subatmospheric pressure.