Abstract: An aluminum titanate ceramic article having a predominant crystal phase of aluminum titanate and a material composition including aluminum, titanium, silica, an alkaline earth metal (e.g., at least one selected from the group of strontium, calcium, barium, or combinations), and a rare earth metal (e.g., at least one selected from the group consisting of yttrium, lanthanum, and combinations) and methods of making such aluminum titanate bodies are described. An oxide of yttrium metal or lanthanide metals is preferably used as a sintering aid in combination with the other compositional components to enable firing of the resulting green body at a lower heating temperature of less than 1500° C., and more preferably between 1400°-1450° C., with a preferable hold time of less than 8 hours, more preferably of 6 to 8 hours.

Abstract: A method of controlling blister formation in a glass melt flowing through a system comprising one ore more refractory metal vessels by developing a blister index and determining the critical blister index value. The critical value of the blister index may be used to control the principal variables responsible for blister formation, including the water content of the melt, the concentration of reduced multivalent oxide compounds in the melt, and the hydrogen partial pressure of an atmosphere in contact with the outside surface of the refractory metal vessel. Also disclosed is a minimum partial pressure of hydrogen necessary to produce an essentially blister-free glass article in a glass essentially free of arsenic and antimony.

Abstract: A family of glasses from the rare earth alumino-silicate (RE2O3-Al2O3-SiO2) ternary system exhibiting high strain point and low liquidus temperatures; preferably the La2O3 -Al2O3-SiO2 ternary system. The glasses are excellent candidates for electronics applications and have the following composition, expressed in mole percent and calculated from the glass batch on an oxide basis: 60-85% SiO2, 10-25% Al2O3, and 4-15% RE2O3.

Abstract: Glasses are disclosed which can be used to produce substrates for flat panel display devices, e.g., active matrix liquid crystal displays (AMLCDs). The glasses have MgO concentrations in the range from 1.0 mole percent to 3.0 mole percent and ?[RO]/[Al2O3] ratios greater than or equal to 1.00, where [Al2O3] is the mole percent of Al2O3 and ?[RO] equals the sum of the mole percents of MgO, CaO, SrO, and BaO. These compositional characteristics have been found to improve the melting properties of batch materials used to produce the glass, which, in turn, allows the glasses to be fined (refined) with more environmentally friendly fining agents, e.g., tin as opposed to arsenic and/or antimony.

Abstract: A method of forming an oxide glass including heating a glass melt having a ?—OH concentration of at least about 0.35 in a vessel comprising a metal selected from the group consisting of platinum, molybdenum, palladium, rhodium, and alloys thereof, there being an interface present between the vessel and the glass, and controlling a partial pressure of hydrogen in an atmosphere in contact with an outside surface of the vessel in an amount such that hydrogen permeation blisters form in a region of the glass adjacent the glass-vessel interface.

Abstract: The invention is directed to ultra-low expansion glasses to which adjustments have been made to selected variables in order to improve the properties of the glasses, and particularly to lower the expansivity of the glasses. The glasses are titania-doped silica glasses. The variables being adjusted include an adjustment in ?-OH level; an adjustment to the cooling rate of the molten glass material through the setting point; and the addition of selected dopants to impact the CTE behavior.

Abstract: A method of making an optical fiber precursor includes generating vapors from an alkali metal source comprising compound containing oxygen and one or more alkali metals and applying the vapors to a surface of a glass article comprising silica at a temperature that promotes diffusion of the alkali metal into the surface of the glass article. An optical fiber has a core comprising silica and an alkali metal oxide of the form X2O, where X is selected from the group consisting of K, Na, Li, Cs, and Rb, wherein a concentration of the alkali metal oxide along a length of the core is uniform.

Abstract: A method of making an alkali metal silicate glass includes preparing an alkali metal feedstock having a first desired level of alkali metal, the alkali metal feedstock being essentially free of an element that absorbs between 0.8 and 2.5 ?m in any valence state. The method also includes combining and mixing the alkali metal feedstock with at least one silicate feedstock to form a precursor material having a second desired level of alkali metal and melting the precursor material to form molten glass.

Abstract: The invention is directed to a glass-ceramic material suitable for use in the manufacturing of EUVL reflective optics. The glass-ceramic materials is made from a composition that comprises (in wt. %): SiO2=64-70; Al2O3=18-24; Li2O=1.6-3.8; MgO=0.8-1.5; ZnO=0.7-4.2; BaO=0.1-1.4; TiO2=2.0-3.5; ZrO2=1.25-2.5; As2O3=0.1-1.0; Na2O<0.5; and K2O<0.5; and the glass-ceramic material has an aggregate coefficient of thermal expansion of ±1 ppm/° C. (±0.1×10?7/° C.) in the temperature range 0-200° C.

Abstract: A method for manufacturing an optical fiber preform and fiber. According to the method, a first glass rod is formed, preferably by an OVD method, with a refractive index delta preferably between 0.2% and 3%. A glass sleeve tube is formed, preferably by an MCVD or PVCD method. The first glass rod is inserted into the sleeve and an alkali metal vapor is flowed between the sleeve tube and the first glass rod. Additional glass may optionally be formed on the inside surface of the sleeve tube prior to inserting the first glass rod and flowing the alkali metal vapor. The additional glass may be up-doped, down-doped, or both. The sleeve may then be collapsed onto the first glass rod to form a second glass rod doped with an alkali metal oxide. The second glass rod is drawn to form a third glass rod. Additional glass may then be formed on the third glass rod to form an optical fiber preform from which optical fiber may be drawn.

Abstract: Glasses are disclosed which are used to produce substrates in flat panel display devices. The glasses exhibit a density less than about 2.45 gm/cm3 and a liquidus viscosity greater than about 200,000 poises, the glass consisting essentially of the following composition, expressed in terms of mol percent on an oxide basis: 65-75 SiO2, 7-13 Al2O3, 5-15 B2O3, 0-3 MgO, 5-15 CaO, 0-5 SrO, and essentially free of BaO. The glasses also exhibit a strain point exceeding 650° C.

Abstract: Disclosed is a process for suppressing monovalent metal ion migration between inorganic materials by placing a barrier layer containing Al2O3 and SiO2 between the inorganic materials. Also disclosed is a process for making silica-containing body comprising a step of forming a barrier layer containing Al2O3 and SiO2 over the soot-receiving substrate before the laydown of the fused silica boule. The barrier layer is effective in suppressing monovalent metal ion migration, especially alkali metal ion, particular sodium ion, migration at elevated temperature. The processes are particularly useful in the production and working of high purity fused silica material required of a very low sodium concentration. The barrier layer material is prepared by using an aqueous suspension comprising silica soot.

Abstract: Disclosed is an optical fiber having a core with an alkali metal oxide dopant in an peak amount greater than about 0.002 wt. % and less than about 0.1 wt. %. The alkali metal oxide concentration varies with a radius of the optical fiber. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained. Also disclosed are several methods of making the optical fiber including the steps of forming an alkali metal oxide-doped rod, and adding additional glass to form a draw perform. Preferably, the draw preform has a final outer dimension (d2), wherein an outer dimension (d1) of the rod is less than or equal to 0.06 times the final outer dimension (d2). In a preferred embodiment, the alkali metal oxide-doped rod is inserted into the centerline hole of a preform to form an assembly.

Abstract: Disclosed is a process for suppressing monovalent metal ion migration between inorganic materials by placing a barrier layer containing Al2O3 and SiO2 between the inorganic materials. Also disclosed is a process for making silica-containing body comprising a step of forming a barrier layer containing Al2O3 and SiO2 over the soot-receiving substrate before the laydown of the fused silica boule. The barrier layer is effective in suppressing monovalent metal ion, especially alkali metal ion, particularly sodium migration at elevated temperature. The processes are particularly useful in the production and working of HPFS® materials required of a very low alkali metal, especially sodium, concentration.

Abstract: A method for the production of glass suitable for use in an optical fiber, by (1) dissolving an optically active component in a solvent to form a solution; (2) mixing the solution and a powder substrate, wherein the powder substrate is insoluble in the solvent; and (3) melting the solution and powder substrate to form glass at a temperature or temperature range that causes melt viscosities at less than or equal to 100,000 poise. A glass made by such a method and an optical fiber comprising such a glass. An optical fiber having optically active ions having an unbleachable loss of 1% or less of the peak of absorption.

Abstract: An isotopically-altered, silica based optical fiber is provided having lower losses, broader bandwidth, and broader Raman gain spectrum characteristics than conventional silica-based fiber. A heavier, less naturally abundant isotope of silicon or oxygen is substituted for a lighter, more naturally abundant isotope to shift the infrared absorption to a slightly longer wavelength. In one embodiment, oxygen-18 is substituted for the much more naturally abundant oxygen-16 at least in the core region of the fiber. The resulting isotopically-altered fiber has a minimum loss of 0.044 dB/km less than conventional fiber, and a bandwidth that is 17 percent broader for a loss range between 0.044-0.034 dB/km. The fiber may be easily manufactured with conventional fiber manufacturing equipment by way of a plasma chemical vapor deposition technique. When a 50 percent substitution of oxygen-18 for oxygen-16 is made in the core region of the fiber, the Raman gain spectrum is substantially broadened.