Abstract: A composition for a glass-ceramic material that contains a crystallinity of at least about 30% by weight of forsterite components at a liquidus temperature of about 1525° C. or below. The glass-ceramic has a composition, in weight percent on an oxide basis, consisting essentially of about: 40-60% SiO2; 10-25% Al2O3; 18-30% MgO; 3-10% Na2O; 0-10% K2O; >5-15% TiO2. The invention further comprises a method for achieving high crystalline yield at such a low liquidus with increased solubility of high levels of chromium ions. The glass-ceramics can be used in drawing optical fibers and as gain media in amplifier and laser devices for near infrared wavelengths.

Abstract: A composition for a glass-ceramic material that contains a crystallinity of at least about 30% by weight of forsterite components at a liquidus temperature of about 1525 ° C. or below. The glass-ceramic has a composition, in weight percent on an oxide basis, consisting essentially of about: 40-60% SiO2; 10-25% Al2O3; 18-30% MgO; 3-10% Na2O; 0-10% K2O; >5-15% TiO2. The invention further comprises a method for achieving high crystalline yield at such a low liquidus with increased solubility of high levels of chromium ions. The glass-ceramics can be used in drawing optical fibers and as gain media in amplifier and laser devices for near infrared wavelengths.

Abstract: A composition for a glass-ceramic material that contains a crystallinity of at least about 30% by weight of forsterite components at a liquidus temperature of about 1525° C. or below. The glass-ceramic has a composition, in weight percent on an oxide basis, consisting essentially of about: 40-60% SiO2; 10-25% Al2O3; 18-30% MgO; 3-10% Na2O; 0-10% K2O; >5-15% TiO2. The invention further comprises a method for achieving high crystalline yield at such a low liquidus with increased solubility of high levels of chromium ions. The glass-ceramics can be used in drawing optical fibers and as gain media in amplifier and laser devices for near infrared wavelengths.

Abstract: The invention includes environmentally stable athermalized optical fiber gratings and methods of making such stabilized optical waveguide fiber grating. Stable humidity-resistant athermalized fiber Bragg gratings are provided by stabilizing a negative thermal expansion substrate and utilizing a durable frit to attach the fiber Bragg grating to the substrate.

Abstract: An athermal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: The invention includes methods of stabilizing negative thermal expansion glass-ceramic optical waveguide substrates. The invention includes the stabilized negative thermal expansion glass-ceramic optical waveguide substrates. The stabilized substrates have very stable physical characteristics such as dimensional length when exposed to extreme environments. The stabilized substrates are used to athermalize optical waveguide devices such as optical fiber grating. The stabilized substrates are particularly well suited for providing athermalized fiber Bragg grating.

Abstract: A composition for a glass-ceramic material that contains a crystallinity of at least about 30% by weight of forsterite components at a liquidus temperature of about 1525° C. or below. The glass-ceramic has a composition, in weight percent on an oxide basis, consisting essentially of about: 40-60% SiO2; 10-25% Al2O3; 18-30% MgO; 3-10% Na2O; 0-10% K2O; >5-15% TiO2. The invention further comprises a method for achieving high crystalline yield at such a low liquidus with increased solubility of high levels of chromium ions. The glass-ceramics can be used in drawing optical fibers and as gain media in amplifier and laser devices for near infrared wavelengths.

Abstract: An athernal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: An athermal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: This invention is directed to the production of thermally crystallizable glasses which can be crystallized in situ via heat treatment into glass-ceramic articles containing a nickel spinelloid as the predominant crystal phase. The glasses consist essentially, in weight percent, of 40-60% SiO.sub.2, 10-35% Al.sub.2 O.sub.3, 5-35% NiO, 0-20% MgO, and 0-15% total TiO.sub.2 and/or ZrO.sub.2. The preferred glasses contain at least 2% MgO.

Abstract: This invention relates to the preparation of a glass exhibiting a transition temperature normally below about 300.degree., a working temperature below about 400.degree., while, at the same time, exhibiting excellent resistance to attack by water. Specifically, the present invention discloses a glass consisting essentially in terms of mole percent on the oxide basis, of 15-35% P.sub.2 O.sub.5, 1-25% SO.sub.3, 30-55% ZnO, 0-25% R.sub.2 O, wherein R.sub.2 O is selected from the group consisting of 0-25% Li.sub.2 O, 0-25% Na.sub.2 O, and 0-25% K.sub.2 O, and up to a total of 15% of optional ingredients in the indicated proportions selected from the group consisting of 0-10% Al.sub.2 O.sub.3, 0-10% MgO, 0-10% CaO, 0-10% SrO, 0-10% BaO, 0-10% MnO, 0-10% transition metal oxides and 0-15% Cl+F, as analyzed in weight percent.

Abstract: This invention relates to glass-ceramic articles containing lithium disilicate crystals as the predominant crystal phase and consisting essentially, in weight percent, of 8-19% Li.sub.2 O, 0-5% Na.sub.2 O, 0-7% K.sub.2 O, 0-8% Na.sub.2 O+K.sub.2 O, 0-10% CaO, 0-6% SrO, 0-6% BaO, 2-12% Na.sub.2 O+K.sub.2 O+CaO+SrO+BaO, 0-7% ZnO, 0-11% Al.sub.2 O.sub.3, 1.5-11% ZnO+Al.sub.2 O.sub.3, with a molar ratio (Na.sub.2 O+K.sub.2 O) (ZnO+Al.sub.2 O.sub.3) between 0.075-1.25, 65-80% SiO.sub.2, and as a nucleating agent 1.5-7% P.sub.2 O.sub.5 and/or 0.0001-0.1% Pd. Glass-ceramics having certain compositions within those ranges are self-glazing.

Abstract: Photosensitively opacifiable glasses requiring very short exposures to ultraviolet radiation to effect the development of opacity are processed by heating to nucleate Ag followed by cooling to nucleate NaF on the Ag followed by heating to grow the NaF. The glasses contain, expressed in terms of weight percent on the oxide basis, about 14-18% Na.sub.2 O, 0-6% ZnO, 6-12% Al.sub.2 O.sub.3, 0-5% B.sub.2 O.sub.3, 65-72% SiO.sub.2, and 0-0.2% Sb.sub.2 O.sub.3, and 0.007-0.04% Ag, 0.008-0.05% CeO.sub.2, 0.7-1.25% Br, and 1.5-2.5% F as analyzed in the glass, the sum of those components are at least 90% of the total composition.

Abstract: This invention is directed to the production of glass-ceramic articles exhibiting an apparent annealing point in excess of 400.degree. C. and excellent resistance to moisture attack, the articles consisting essentially, in mole percent, of:______________________________________ Li.sub.2 O 5-25 ZnO 35-50 Na.sub.2 O 0-15 Al.sub.2 O.sub.3 0.75-6 K.sub.2 O 0-10 P.sub.2 O.sub.5 29-37. Li.sub.2 O + Na.sub.2 O + K.sub.

Abstract: There is disclosed a lithium aluminosilicate glass body encased within, and integral with, a thin, compressive, semicrystalline layer containing beta-eucryptite and/or beta-quartz solid solution crystals, and a method of producing such body. The layer has a substantially lower thermal coefficient of expansion than the glass, but has the same chemical composition as the glass. That composition, in percent by weight on a calculated oxide basis is 55-67% SiO.sub.2, 5.0-7.5% Li.sub.2 O, 22-28% Al.sub.2 O.sub.3, 0-2% Na.sub.2 O and 0-10% ZnO, the molar ratio of R.sub.2 O+RO to Al.sub.2 O.sub.3 being greater than one. Controlled crystallization procedure is described whereby the crystallized layer can be produced in a relatively short time.

Abstract: This invention is directed to the production of unitary, transparent glass articles demonstrating exceptionally high flexural and impact strengths composed of an interior portion and an integral surface compression layer. The articles are prepared by contacting glass bodies consisting essentially, in mole percent, of 14-24% R.sub.2 O, wherein R.sub.2 O consists of 0-5% Li.sub.2 O, 0-5% K.sub.2 O, and the remainder Na.sub.2 O, 17-21% Al.sub.2 o.sub.3, 45-60% SiO.sub.2, 3-6% TiO.sub.2 and/or ZrO.sub.2, and 0-2% P.sub.2 O.sub.5, the sum of those components constituting at least 85% of the total composition, at a temperature above the annealing point of the glass with a source of Li.sup.+ ions to replace at least part of the Na.sup.+ ions and, if present, K.sup.+ ions in a surface layer with a corresponding amount of Li.sup.+ ions and to react the Li.sup.+ ions with Al.sub.2 O.sub.3 and SiO.sub.2 in the surface layer to form crystallites of beta-quartz solid solution nucleated by the TiO.sub.2 and/or ZrO.sub.2.

Abstract: The present invention is concerned with glass-ceramic articles which are extremely resistant to impact and spontaneous delayed breakage, are capable of being sawn with a diamond wheel to a depth of over one-third the cross section thereof without breakage, and exhibit modulus of rupture values of at last 150,000 psi. The articles consist of a body portion and an integral surface compression layer having a depth of at least 0.005". The body portion consists essentially, in weight percent, of about 8-13% Na.sub.2 O, 7-13% K.sub.2 O, 30-36% Al.sub.2 O.sub.3, 35-43% SiO.sub.2, and 6-10% RO.sub.2, wherein RO.sub.2 consists of 6-10% TiO.sub.2 and 0-4% ZrO.sub.2, wherein the molar ratio Al.sub.2 O.sub.3 :SiO.sub.2 is >0.5 but <0.6 and the molar ratio K.sub.2 O:Na.sub.2 O is >1:3 but <1 and contains nepheline solid solution crystals corresponding to the formula Na.sub.8-x K.sub.x Al.sub.8 Si.sub.8 O.sub.32, with x varying from 0.25-4.73, as the predominant crystal phase.

Abstract: The present invention is concerned with glass-ceramic articles which are extremely resistant to impact and spontaneous delayed breakage, are capable of being sawn with a diamond wheel to a depth of over one-third the cross section thereof without breakage, and exhibit modulus of rupture values of at least 150,000 psi. The articles consist of a body portion and an integral surface compression layer having a depth of at least 0.005". The body portion consists essentially, in weight percent, of about 8-13% Na.sub.2 O, 7-13% K.sub.2 O, 30-36% Al.sub.2 O.sub.3, 35-43% SiO.sub.2, and 6-10% RO.sub.2, wherein RO.sub.2 consists of 6-10% TiO.sub.2 and 0-4% ZrO.sub.2, wherein the molar ratio Al.sub.2 O.sub.3 :SiO.sub.2 is >0.5 but <0.6 and the molar ratio K.sub.2 O:Na.sub.2 O is >1:3 but <1 and contains nepheline solid solution crystals corresponding to the formula Na.sub.8-x K.sub.x Al.sub.8 Si.sub.8 O.sub.32, with x varying from 0.25-4.73, as the predominant crystal phase.

Abstract: This invention is related to the production of glasses having compositions within the copper and/or silver-halide-phosphate field, wherein at least one halide is present selected from the group of fluoride, chloride, bromide, and iodide, such glasses exhibiting softening points below about 400.degree. C., coefficients of thermal expansion (25.degree.-300.degree. C.) in excess of about 180.times.10.sup.-7 /.degree.C., high electrical conductivity, and electrochromic behavior. The copper-containing glasses may also demonstrate thermochromic properties.

Abstract: The present invention is concerned with a single-step process for hydrating alkali metal-containing silicate glasses starting with such fine-dimensioned forms as powders, granules, flakes, fibers, and thin sheets. The process, which contemplates hydration temperatures higher than 225.degree. C. and relative humidities less than 50%, permits the precise control of the quantity of water taken into the glass structure and, where the water content in the glass is held within about 1-25% by weight, the hydrated product of the above-cited powders, granules, etc., can be thermoplastically formed into sound bulk articles. A layer of the anhydrous powders can be applied to a substrate and then hydrated in situ to form glassy paints and coatings.