Abstract: This invention is directed to the production of glass bodies containing crystallites of PbS and/or PbSe. The crystallite-containing bodies are formed by the thermal crystallization in situ of glass bodies having compositions essentially free from CdO and consisting essentially, expressed in terms of weight percent on the oxide basis except for fluorine, sulfur, and selenium which are expressed in terms of weight percent on the elemental basis, of______________________________________ SiO.sub.2 58-65 RO 0-15 Na.sub.2 O 10-15 F 1-3.5 ZnO 5-17 S 0-3 Al.sub.2 O.sub.3 0.5-5 Se 0-3 PbO 3-6 S + Se 1-3 ______________________________________wherein RO consists of at least one alkaline earth metal oxide in the indicated proportions selected from the group consisting of 0-5% BeO, 0-5% MgO, 0-15% CaO, 0-10% SrO, and 0-10% BaO.

Abstract: There is disclosed a venting system adapted to direct air flow over the inside of an eyeglass lens to minimize a tendency to fog. The venting system may be an integral part of a pair of eyeglasses, or may be incorporated in a separate member, in particular a shielding cassette, adapted to be used with a pair of eyeglasses.

Abstract: Thin inorganic sintered structures having strength and flexibility sufficient to permit bending without breakage in at least one direction to a radius of curvature of less than 20 centimeters, methods for making them, and products incorporating them, are described. Preferred sintered ceramic structures according to the invention can comprise zirconias, titanias, aluminas, silicas, rare earth metal oxides, alkaline oxides, alkaline earth metal oxides and first, second, and third transition series metal oxides and combinations thereof and therebetween. Sintered metal structures can also be provided.

Abstract: There is disclosed a sintered, alpha-cordierite solid solution glass-ceramic body in which the properties of coefficient of thermal expansion and modulus of rupture are stabilized and controlled by using a combination of two dopants in the glass during sintering and crystallization. There is further disclosed the method of producing such bodies, and controlling such properties, through the use of the two dopants.

Abstract: There is disclosed a method of producing a multifocal, ophthalmic lens blank wherein a glass major element is formed that has a raised countersink zone on one surface, the remainder of the glass major element being thinner than the countersink zone, but of such thickness that it can be ground and polished to form a lens, a countersink is formed in the countersink zone, a segment element is formed and is fused in the countersink to form a lens blank assembly.

Abstract: There are disclosed fluoroborosilicate glasses that are particularly adapted to being drawn with lead silicate core glasses to produce clad glass fibers useful in forming fiber optic bundles to be incorporated in night vision equipment. The cladding glass has a refractive index not over about 1.465 and a coefficient of thermal expansion not over about 80.times.10.sup.-7 /.degree.C. The clad fiber has a numerical aperture approximating or equal to one.

Abstract: There is disclosed a method of treating phyllosilicate materials by exposing the materials to a source of hydrogen ions to hydrate hydroxyl ions on and in the phyllosilicate structure. The source of hydrogen ions may be a simple organic, or mineral, acid, preferably formic or hydrochloric acid. The hydrated phyllosilicate may then be dehydrated and delaminated by thermal treatment.

Abstract: There is disclosed an optical element having a pattern of raised optical elements integral with a surface thereof, and a metal coating selectively covering the surface intermediate the optical elements to form a mask optically isolating the elements. Several methods of producing such metal coating are disclosed that employ conventional photoresist materials and means of applying and removing such materials. Also, a modified element, that is adapted to use in a liquid crystal display device, and methods of producing such modified element are disclosed.

Abstract: There is disclosed a highly densified, sintered aluminum nitride body having a thermal conductivity in excess of 200 W/m.degree.K. and a strong resistance to attack by hot HC1. There is also disclosed a method of sintering aluminum nitride bodies which employs a variable thermal cycle whereby the body is either heated slowly through a pre-sintering temperature range of 1300.degree. to 1750.degree. C., or held at a temperature within that range for at least a half hour. Optionally, a green aluminum nitride body may be provided with up to 10% by weight of at least one metal fluoride dopant, and may be provided with a sufficient weight to maintain flatness during firing.

Abstract: The present invention is directed to a four-step process for molding glass articles of high precision and excellent surface figure. A glass preform having an overall geometry closely approximating that of the desired final product is placed into a mold, the mold and preform are brought to a temperature at which the glass exhibits a viscosity between 10.sup.8 -10.sup.12 poises, a load is applied to shape the glass into conformity with the mold, and thereafter the glass shape is removed from the mold at a temperature above the transformation range of the glass and annealed.

Abstract: The present invention is directed to the production of glass and glass-ceramic compositions which have particular utility as culinary utensils inasmuch as they are exceptionally easy to clean after food has been burned thereon. The products have at least an integral surface layer which contains MgO-based and/or CaO-based and/or SrO-based and/or BaO-based crystals as the predominant crystal phase. Operable compositions consist essentially, expressed in weight percent on the oxide basis, of 14.8-19.6% MgO, 16.2-20.0% Al.sub.2 O.sub.3, and 58.7-66.5% SiO.sub.2, when said surface layer contains MgO-based crystals as the predominant crystal phase, 22.2-31.6% CaO, 42.8-53.9% Al.sub.2 O.sub.3, and 23.8-33.6% SiO.sub.2, when said surface layer contains CaO-based crystals as the predominant crystal phase, 31-48% SrO, 24-35.7% Al.sub.2 O.sub.3, and 28-35% SiO.sub.2, when said surface layer contains SrO-based crystals as the predominant crystal phase, and 42.4-45% BaO, 10-15.9% Al.sub.2 O.sub.3, and 41.7-45% SiO.sub.