Abstract: The heat resisting fiber-reinforced composite material of the invention is a heat-resisting fiber-reinforced composite material used for a product or a part that generates temperature disribution; wherein the thermal expansion coefficient at a portion corresponding to a medium to low temperature range is greater than the thermal expansion coefficient at a portion corresponding to a high temperature range, and the boundary between the portion corresponding to medium to low temperature range and the portion corresponding to the high temperature range is a transition region.

Abstract: A mineral fiber composition which is soluble in biological fluids contains substantially 45-65% by weight of SiO2 15-40% by weight of CaO 0-20% by weight of MgO 0-6% by weight of Na2O+K2O and in addition aluminium and/or iron oxides as well as phosphorus oxide in such amounts that the weight ratio of P2O5 to the sum of Al2O3 and iron oxide is circa 0.4 to 6.

Abstract: Low-boron, high-barium glass compositions and fine-diameter glass fibers for forming clean room HEPA and ULPA filters, are provided. The compositions and resulting glass fibers preferably comprise a low concentration, less than about 1 weight percent, of boric oxide, a relatively high concentration of barium, such as from about 5.5 to about 18 weight percent barium oxide, and a concentration of alkali oxide ranging from about 10 to about 14.5 weight percent. Alumina is preferably present in the glass fiber compositions and the resulting glass fibers in a range of from about 4 weight percent to about 8 weight percent, and calcium oxide and magnesium oxide are preferably present in a range of from about 1 weight percent to about 6 weight percent and from about 0 weight percent to about 3.5 weight percent, respectively. The glass fiber compositions also preferably include from about 2 to about 6 weight percent zinc oxide, from about 0.1 to about 1.

Abstract: An article and method for its manufacture are described. The article is preferably a ladle used in the manufacture of metals and receives molten metal for further chemical processing in the ladle or for transportation. The ladle is transparent to a wide range of electromagnetic radiation wavelengths which allows the metal to be heated or stirred by induction without heating the ladle itself. The ladle is made of glass fibers and an inorganic cement, and this provides strength along with high temperature resistance. The article is manufactured by winding glass fiber around a mandrel, the glass fiber having an inorganic cement adhered to it. In one technique, the cement is provided on the fiber as an aqueous slurry, and the product is allowed to air cure after winding. In a second technique, the cement is adhered to the fiber by electrostatic attraction.

Abstract: A glass powder for glass ionomer cement is disclosed, containing a glass powder for glass ionomer cement having a shape in which a major axis length is from 3 to 1,000 times a minor axis length, in a glass powder for glass ionomer cement. The glass powder for glass ionomer cement having a shape in which a major axis length is from 3 to 1,000 times a minor axis length is a fibrous glass having a minor axis length of from 0.1 to 100 &mgr;m and a major axis length of 500 &mgr;m or less, and its content is within a range of from 0.1 to 80% by weight, being enable to provide a glass ionomer cement set material having a high mechanical strength, particularly bending strength and tensile strength.

Abstract: Man-made vitreous fibers have a solubility of pH 4.5 of at least 20 nm per day and a melt viscosity of 10 to 70 poise at 1400° C. Novel fibers contain at least 18% Al2O3. Particular products include external wall insulation or cladding and pipe sections. A composition for making suitable fibres may be selected by determining solubility at pH 4.5 or in macrophage.

Abstract: Glass fibers prepared by flame attenuation display excellent chemical resistance to both acids and moisture while being highly biosoluble at the same time. The glass compositions are characterized by ratios of components which are reflective of acid resistance, biosolubility, and moisture resistance. Preferred glass fibers exhibit a biodissolution greater than about 350 ng/cm/2hr.

Abstract: Man-made vitreous fibers have a solubility of pH 4.5 of at least 20 nm per day and a melt viscosity of 10 to 70 poise at 1400° C. Novel fibers contain at least 18% Al2O3. Particular products include external wall insulation or cladding and pipe sections. A composition for making suitable fibres may be selected by determining solubility at pH 4.5 or in macrophage.

Abstract: The present invention provides a method for the manufacture of ceramic composite fibers, and the present invention relates to a method for the manufacture of a composite fiber in which a second phase is dispersed within a matrix fiber, wherein the matrix consists of a substance selected from alumina, zirconia, mullite, YAG, silica, magnesia, nitrides, carbides, metals, alloys, and polymers; the second phase consists of a substance selected from zirconia, mullite, YAG, and other oxides, or from metals; and the composite fiber is produced by synthesizing a fiber from a precursor solution containing the substance of the matrix, and the starting solution which serves as the second phase, dispersed through the matrix solution, and then heating the fiber.

Abstract: A low-dielectric-constant glass fiber having a glass composition comprising, by % by weight, 45 to 60% of SiO2, 8 to 20% of Al2O3, 15 to 30% of B2O3, 0 to 5% of MgO, 5%, exclusive of 5%, to 12% of CaO, 0 to 1.0% of Li2O+Na2O+K2O, 0.5 to 5% of TiO2 and 0 to 2% of F2 is suitable for use for reinforcing a high-density printed wiring board required to have a low dielectric tangent and its peripheral members.

Abstract: An insulation product especially suited for use as an aircraft insulation includes a blanket of randomly oriented entangled glass fibers bonded together by a thermosetting binder and having a mean diameter of about 1+/−0.25 microns. The blanket has a density between about 0.25 and about 1.5 pounds per cubic foot and a thickness between about 0.35 inches and about 2.0 inches. The blanket, exclusive of anything else, has an average machine direction tensile strength of at least 0.6 pounds/inch of blanket width and an average cross machine direction tensile strength of at least 0.3 pounds/inch of blanket length; a transverse airflow resistance between about 300 Rayls and about 1800 Rayls; and a thermal conductivity equal to or less than about 0.32 BTU-in/hr-ft2-° F. The glass fibers of the blanket have a biodissolution rate in excess of 150 ng/cm2/hr.

Abstract: Novel boron-free glass compositions are described which are particularly suited for making fine diameter glass fibers for HEPA electronic clean-room filtration media using flame-attenuation or rotary glass processing.

Abstract: A mineral fiber composition having enhanced biosolubility characteristics, comprising by percentage weight: Al2O3 16 to 25 CaO >29 SiO2 30 to 40 MgO <15 Iron <5, selected from the group consisting of Fe, FeO and Fe2O3 K2O <4 P2O5 <0.8 The Kdis of the mineral fiber composition is in the range of greater than 1000 (ng/cm2 * hr) at pH 4.5.

Abstract: The invention concerns a mineral fibre having the following composition in % by weight: SiO2 50-60, A12O3 1-6, MgO 16-22, CaO 12-18, Na2O+K2O 0-3, Fe2 O31-8, P2O5 1-6, other 0-3, whereby the weight ratio CaO/MgO<1 and the sum CaO+MgO=30-38% by weight.

Abstract: A ferrite sintered compact, as an element of an electronic part for forming an internal conductor containing silver, includes a ferrite containing at least two components selected from the group consisting of nickel, zinc and copper, and a glass having a viscosity at 650 to 850.degree. C. of about 10.sup.10 Pa.multidot.s or more.

Abstract: Man-made vitreous fibers have a solubility at pH 4.5 of at least 20 nm per day, a liquidus temperature of below 1300.degree. C., a viscosity at the liquidus temperature of about 300 poise, and a composition which includes at least 15% by weight Al.sub.2 O.sub.3.

Abstract: The present invention relates to reinforcing glass yarns, the composition of which comprises the following constituents within the limits defined hereinbelow, expressed in percentages by weight:______________________________________ SiO.sub.2 58 to 62% Al.sub.2 O.sub.3 10 to 16% CaO more than 18% MgO more than 1.5% CaO + MgO less than 28% Na.sub.2 O + K.sub.2 O + Li.sub.2 O less than 2% TiO.sub.2 less than 1.5% Fe.sub.2 O.sub.3 less than 0.5% B.sub.2 O.sub.3 less than 2% F.sub.2 less than 2% ______________________________________this composition furthermore comprising less than 1% of other constituent(s) and comprising more than 0.5% of at least one of the three components F.sub.2, B.sub.2 O.sub.3 and Li.sub.2 O.These yarns have a composition providing an excellent compromise between its cost and its fiberizability.

Abstract: A process for the preparation of molten mineral compositions wherein organic impurities are removed by reaction with oxygen introduced via the decomposition of calcium peroxide.

Abstract: Composite materials formed from bone bioactive glass or ceramic fibers and structural fibers are disclosed. In preferred embodiments, a braid or mesh of interwoven bone bioactive glass or ceramic fibers and structural fibers is impregnated with a polymeric material to provide a composite of suitable biocompatibility and structural integrity. Most preferably, the mesh or braid is designed so that the bioactive fibers are concentrated at the surface of the implant to create a surface comprised of at least 30% bioactive material, thereby providing enhanced bone ingrowth. The interweaving between the bone bioactive glass or ceramic fibers and the core of structural fibers overcomes the problems found in prior composite systems where the bioactive material delaminates from the polymer. Preferred bioactive materials include calcium phosphate ceramics and preferred structural fibers include carbon fibers. Further preferred bioactive materials include aluminum oxide at greater than 0.2%, by mole.

Abstract: A method of producing a homogeneous metal oxide fiber having high denseness and free of voids that may adversely affect the electro-optic characteristic of the fiber, and a metal oxide fiber produced according to the method. The method comprises:a first step of forming a gel-form fiber from a sol obtained by concentrating a solution composed of a metallic compound, water and a solvent to the extent that the solution exhibits a spinnable behavior;a second step of decomposing and eliminating organic components out of the gel-form fiber obtained at the first step; anda third step of solidifying the gel-form fiber obtained at the second step;the second step and/or the third step being carried out while heating is made in a water vapor atmosphere.

Abstract: Glass compositions displaying decreased far infrared radiation transmission, high biosolubility, and excellent moisture resistance are capable of fiberization by the rotary process, and may be used to prepare thermal insulation products exhibiting high thermal insulation efficiency as reflected by low thermal index values. The insulation products also exhibit excellent stiffness and recovery properties.

Abstract: A composition for a bulk conducting glass comprising P.sub.2 O.sub.5, V.sub.2 O.sub.5, PbO, and FeO, the ratio of the molar percentage of P.sub.2 O.sub.5 to V.sub.2 O.sub.5 being in the range of about 1 to about 6, and the P.sub.2 O.sub.5 and V.sub.2 O.sub.5 being present in an aggregate amount of at least about 50 mole percent, the PbO being present in the glass in an amount in excess of 15 mole percent, and the FeO being present in amount of about 0 to about 30 mole percent. The composition may also include MnO or Sb.sub.2 O.sub.3 in an amount of up to about 2 mole percent. The composition may be formed into fibers for use in microchannel plates and other devices where bulk conductivity in glass is advantageous.

Abstract: Chalcogenide glass fibers having a glass core with two cladding glass layers, the second cladding glass layer having a refractive index lower than that of the core glass and higher than that of the first cladding glass. The core glass does not contain germanium. Glass fiber having this core-cladding structure is mechanically strong and exhibits only small transmission loss of infrared light passing through the fiber.

Abstract: The present invention provides a process for producing aluminum oxide fibers and, particularly, a process for producing aluminum fibers that have a high aspect ratio and can be accurately aligned, said process for producing aluminum oxide fibers comprising the steps of: uniformly mixing an aluminum or aluminum alloy powder with a boron oxide powder or a powder which, upon heating, can be converted to a boron oxide powder; and heating the mixed powder, or comprising the steps of: mixing not more than 50% by weight, in terms of titanium, of a titanium or titanium alloy powder to the starting mixture; and heating the mixed powder.

Abstract: The present invention relates to mineral fiber composition which can dissolve in contact with a physiological medium. The composition of these fibers includes the following components, in accordance with the following proportions by weight:______________________________________ SiO.sub.2 48 to 67% Al.sub.2 O.sub.3 0 to 8% Fe.sub.2 O.sub.3 0 to 12% ______________________________________(total iron expressed in this form) ______________________________________ CaO 16 to 35% MgO 1 to 16% Na.sub.2 O + K.sub.2 O 0 to 6.5% P.sub.2 O.sub.5 0 to 5% ______________________________________taking into consideration that these compositions are also defined by the fact that the contents of these components comply with the following ratios:Na.sub.2 O+P.sub.2 O.sub.5 .gtoreq.2%Fe.sub.2 O.sub.3 +Al.sub.2 O.sub.3 .ltoreq.12%CaO+MgO+Fe.sub.2 O.sub.3 .gtoreq.23%.

Abstract: An optical fiber amplifier is formed from glass doped with praseodymium. The glass may include one or more of cadmium mixed halide, hafnium halides, geranium and silicon disulphide based vitreous materials or fluorozirconate glass fibers.

Abstract: The glass compositions of the present invention contain at least 2.0 wt % Al.sub.2 O.sub.3 to give resulting glass fiber an acceptable chemical durability for product performance, but no more than 3.0 wt % to ensure the fiber maintains a relatively high biosolubility. The compositions further include relatively high amount of Na.sub.2 O+K.sub.2 O+MgO+CaO, which tends to increase fiber biosolubility and allows for the use of reduced amounts of B.sub.2 O.sub.3 in the composition. The glass compositions have KI values that generally equal or exceed a KI value of 40 and are suitable for rotary processing. The compositions have liquidus temperatures below about 1800.degree. F. and viscosities above 300 Poise at the liquidus temperature. For higher B.sub.2 O.sub.3 compositions the liquidus temperatures are below 1650.degree. F., and the viscosities are above 1,000 Poises at the liquidus temperatures.

Abstract: Compositions for producing irregularly-shaped dual-glass fibers include a first glass composition and a second glass composition, the first and second glass compositions having nonidentical coefficients of thermal expansion, the difference between the coefficients of thermal expansion being greater than about 2.0 ppm/.degree. C.

Abstract: A reinforcement for composite materials is disclosed, which comprises a number of filaments of inorganic long fiber and glass and/or glass ceramic present in the gaps among the filaments and having a wire or tape form. Also disclosed is a metallic or ceramic composite material composed of a plurality of the reinforcements and a metal or intermetallic compound or ceramic which is present in the gaps among the individual reinforcements.

Abstract: Disclosed is use of a vitreous inorganic fiber in the knowledge that it has a composition meeting the criterion that the calculated sum of the free energies of hydration of the compounds that would or could be present at equilibrium (on the basis of knowledge, informed belief or reasonable assumption) is more negative than -10 kcal/100 grams of composition. Such compositions are saline soluble.

Abstract: Described is an inorganic fiber comprising silica dioxide, calcium oxide, and alkali oxide having a free energy of hydration greater than (more positive than) -5.00 kcal/mol, an enthalpy of formation less than (more than negative than) -210.0 kcal/mol, a dissolution rate in simulated extra cellular fluid greater than 750 (calculated as nanograms of fiber/per square centimeter of fiber surface area/per hour) having an average fiber diameter not greater than 4.5 micrometers. Also described is a method of manufacturing the fibers.

Abstract: A fiberizable glass composition which has a KI value .gtoreq.40, while possessing acceptable processing properties such as viscosity and liquidus temperatures is provided. The glass composition processes well in the furnace with acceptably low levels of foaming and is readily fiberizable. The glass has a high boron content, a high soda content, and contains only small amounts of alumina. Further, the glass contains small amounts of barium sulfate which improves the durability of the glass fibers in use.

Abstract: The low-dielectric-constant glass fiber of the present invention contains by weight, as a glass composition, 50 to 60% of SiO.sub.2, 10 to 20% of Al.sub.2 O.sub.3, 20 to 30% of B.sub.2 O.sub.3, 0 to 5% of CaO, 0 to 4% of MgO, 0 to 0.5% of Li.sub.2 O+Na.sub.2 O+K.sub.2 O and 0.5 to 5% of TiO.sub.2, and is preferably used as glass for printed wiring boards.

Abstract: An improved fiber reinforced glass composite includes a boron-containing refractory fiber having its surface enriched with boron nitride 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 or non-cyclic siloxane monomers containing a vinyl group attached to silicon and/or a hydride-silicon group. The boron nitride-containing fiber is the product of treating the boron-containing fiber with ammonia at a temperature between about 1100.degree. C. and 1250.degree. C. Fibrous failure rather than brittle failure under stress can be obtained.

Abstract: The invention relates to "two-component" inorganic fibers obtained by conjoint fiber formation from two different inorganic compositions, especially two glass compositions based on SiO.sub.2, alkali metal oxides and alkaline-earth metal oxides;the two inorganic compositions have thermal expansion coefficients .alpha. exhibiting a difference .DELTA..alpha. of at least 20.times.10.sup.7 K.sup.-1,they have a minimum viscosity temperature of fiber formation T.sub.log3 of between 830 and 1010.degree. C.,they exhibit a work range of at least 30.degree. C.,each includes, as weight percentages, in all less than 3% of the following compounds: TiO.sub.2, ZnO, BaO and Li.sub.2 O and preferably less than 1% of each of these,they exhibit, as weight percentages, differences in respective contents of boron oxides B.sub.2 O.sub.3 and of sodium oxide Na.sub.2 O such that:(i) .DELTA.B.sub.2 O.sub.3 >2%(ii) .DELTA.Na.sub.2 O>2%.

Abstract: Glass compositions suitable for pot and marble fiberization display excellent chemical resistance to both acids and moisture while being highly biosoluble at the same time. The glass compositions are characterized by ratios of components which are reflective of acid resistance, biosolubility, and moisture resistance. Preferred glasses have a difference between HTV (10.sup.3 poise) and liquidus greater than 500.degree. F., and a biodissolution greater than about 350 ng/cm.sup.2 /hr.

Abstract: Mineral fiber compositions are disclosed which, in a first embodiment, include the following components, indicated in weight percents: about 54 to about 70 percent SiO.sub.2, about 0 to about 4 percent Al.sub.2 O.sub.3, about 0 to about 6 percent Na.sub.2 O, about 0 to about 6 percent K.sub.2 O, about 0 to about 6 percent MgO, about 10 to about 28 percent CaO, about 6 to about 17 percent total iron as FeO, and about 0 to about 5 percent TiO.sub.2, wherein the total weight percent of SiO.sub.2 and Al.sub.2 O.sub.3 ranges from about 56 percent to about 72 percent, the total weight percent of MgO and CaO ranges from about 12 percent to about 28 percent, the total weight percent of Na.sub.2 O and K.sub.2 O does not exceed 6 percent, and the total weight percent of all components, including trace elements, if any, is 100 percent. In a second embodiment, the compositions include the following components, indicated in weight percents: about 50 to about 68 percent SiO.sub.2, about 0 to about 4 percent Al.sub.2 O.sub.

Abstract: Glass compositions displaying decreased far infrared radiation transmission, high biosolubility, and excellent moisture resistance are capable of fiberization by the rotary process, and may be used to prepare thermal insulation products exhibiting high thermal insulation efficiency as reflected by low thermal index values.

Abstract: The present invention relates to glass fibers, especially for reinforcing organic materials and having an alumino-silicate glass composition, containing one or more alkaline earth metal compounds and with a low content of alkali metal compounds, wherein the composition further contains a combination of coloring agents formed from iron oxides, cobalt oxide and, optionally, chromium oxide, which enable the fibers to be dyed in bulk and to have more neutral tones.

Abstract: An inorganic glass having an aliphatic polymer covalently bonded to the surface thereof is disclosed for providing improved adhesion to a matrix polymer when the glass is employed as a composite filler, as well as for the formation of a composite absent a separate matrix polymer. The polymer is grafted onto the glass by a method which includes the steps of pretreating the surface of the glass with an activator which an activating moiety to the surface, functionalizing the pretreated surface by bonding functional moieties thereto, and polymerizing a cycloaliphatic monomer onto the functionalized surface in the presence of a ring opening polymerization catalyst. Also disclosed are novel inorganic glasses which contain both silicate and phosphate linkages.

Abstract: A composition useful as a restorative material includes a curable matrix with whiskers which preferably have a silicon dioxide containing coating thereon that are then silanized and may also include optional particulate filler of the type which may release fluorides. The polymeric matrix bonds more tightly to the whiskers due to the coating of silicon dioxide on the surface of the whiskers and the coaction between said silicon dioxide and the silane compound. Particles adhered to the whisker also enhance the mechanical properties by virtue of the whisker's surface being thereby roughened. A method of manufacture is also disclosed.

Abstract: A mineral fibre composition which is soluble in biological fluids contains substantially45-65% by weight of SiO.sub.215-40% by weight of CaO0-20% by weight of MgO0-6% by weight of Na.sub.2 O+K.sub.2 Oand in addition aluminium and/or iron oxides as well as phosphorus oxide in such amounts that the weight ratio of P.sub.2 O.sub.5 to the sum of Al.sub.2 O.sub.3 and iron oxide is circa 0.4 to 6.

Abstract: A saline soluble fibre is disclosed that is highly refractory. A vacuum cast preform of the fibre has a shrinkage of 3.5% or less when exposed to 1260.degree. C. for 24 hours. The fibre may comprise CaO, SiO.sub.2, MgO optionally ZrO.sub.2, optionally less than 0.75 mol % Al.sub.2 O.sub.3, any incidental impurities amounting to less than 2 mol % in total, and in which the SiO.sub.2, excess (defined as the amount of SiO.sub.2 calculated as remaining after the above named constituents are crystallised as silicates) exceeds 21.8 mol %, with the proviso that, if the amount of CaO is greater than the sum of the amount of MgO and twice the amount of ZrO.sub.2 the calculated ratio of diopside to wollastonite does not lie in the range 1.8 to 5.25. Such fibres are usable at elevated temperatures where refractoriness is of importance and their solubility in saline solution may make the fibres safer than non-soluble fibres.

Abstract: The present invention relates to mat-shaped composites having porosities above 60% and densities below 0.6 g/cm.sup.3, comprising an aerogel and fibers dispersed therein, the aerogel having cracks and the aerogel fragments enclosed by the cracks, whose average volume is 0.001 mm.sup.3 to 1 cm.sup.3, being held together by the fibers. The present invention further relates to processes for producing the composites of the invention and to their use.

Abstract: A glass fiber insulation product includes irregularly-shaped glass fibers of two different glasses having differing coefficients of thermal expansion, with the irregularly-shaped dual-glass fibers exhibiting a substantially uniform volume filling nature, and providing improved recovery and thermal conductivity abilities even in the absence of a binder material.

Abstract: Composite materials formed from bone bioactive glass or ceramic fibers and structural fibers are disclosed. In preferred embodiments, a braid or mesh of interwoven bone bioactive glass or ceramic fibers and structural fibers is impregnated with a polymeric material to provide a composite of suitable biocompatibility and structural integrity. Most preferably, the mesh or braid is designed so that the bioactive fibers are concentrated at the surface of the implant to create a surface comprised of at least 30% bioactive material, thereby providing enhanced bone ingrowth. The interweaving between the bone bioactive glass or ceramic fibers and the core of structural fibers overcomes the problems found in prior composite systems where the bioactive material delaminates from the polymer. Preferred bioactive materials include calcium phosphate ceramics and preferred structural fibers include carbon fibers. Further preferred bioactive materials include aluminum oxide at greater than 0.2%, by mole.

Abstract: A reinforcing composition is provided comprising pellets produced by the process of hydrating glass fibers to achieve a water content on the glass fibers of from about 11 weight percent to about 20 weight percent, mixing the glass fibers for at least about three minutes, thereby forming pellets, and drying.

Abstract: Coated ceramic filler materials comprised of ceramic particles, fibers, whiskers, etc. having at least two substantially continuous coatings thereon are provided. The coatings are selected so that the interfacial shear strength between the ceramic filler material and the first coating, between coatings, or between the outer coating and the surrounding matrix material, are not equal so as to permit debonding and pull-our when fracture occurs. The resultant, multi-coated ceramic filler materials may be employed to provide composites, especially ceramic matrix composites, with increased fracture toughness. The ceramic filler materials are designed to be particularly compatible with ceramic matrices formed by directed oxidation of precursor metals, but such ceramic filler materials are also adaptable for use in many other composite material systems.In a preferred embodiment, the coatings are applied to the ceramic fiber plies or preforms by CVD.

Abstract: A glass fiber insulation product includes irregularly-shaped glass fibers of two different glasses having differing coefficients of thermal expansion, with the irregularly-shaped dual-glass fibers exhibiting a substantially uniform volume filling nature, and providing improved recovery and thermal conductivity abilities even in the absence of a binder material.

Abstract: This invention is directed broadly to transparent glasses exhibiting excellent transmission far into the infrared region of the electromagnetic radiation spectrum, those glasses consisting essentially, expressed in terms of mole percent, of 40-80% Ga.sub.2 S.sub.3, 0-35% RS.sub.x, wherein R is at least one network forming cation selected from the group consisting of aluminum, antimony, arsenic, germanium, and indium, 1-50% Ln.sub.2 S.sub.3, wherein Ln is at least one cation selected from the group consisting of a rare earth metal cation and yttrium, 1-45% MS.sub.x, wherein M is at least one modifying metal cation selected from the group consisting of barium, cadmium, calcium, lead, lithium, mercury, potassium, silver, sodium, strontium, thallium, and tin, and 0-10% total chloride and/or fluoride. Glass compositions consisting essentially, expressed in terms of mole percent, of 5-30% Ga.sub.2 S.sub.3, 0-10% R.sub.2 S.sub.