Abstract: This invention is directed to transparent photochromic glasses that can darken to a comfort range, i.e., between about 35-60%, or to a dark range, i.e., below 35%, depending upon glass composition, and will exhibit a faded transmittance after five minutes' removal from actinic radiation higher than 70%. The base compositions of the glasses consist essentially, in weight percent, of about______________________________________ SiO.sub.2 46-60 MgO 0-3.5 B.sub.2 O.sub.3 16-28 CaO 0-6 Al.sub.2 O.sub.3 4-11 SrO 0-6 ZrO.sub.2 2-6 BaO 0-6 Al.sub.2 O.sub.3 + ZrO.sub.2 6-13 MgO + CaO + SrO + BaO 0-7 Li.sub.2 O 2-5 P.sub.2 O.sub.5 0-5 Na.sub.2 O 0-4 TiO.sub.2 0-3 K.sub.2 O 2.5-9 ______________________________________For a comfort glass the photochromic elements consist essentially, as analyzed, of ______________________________________ Ag 0.13-0.18 Br 0.08-0.14 Cl 0.16-0.34 CuO 0.001-0.

Abstract: This invention is directed to the production of inorganic crystalline fibers containing a minor amount of Mo0.sub.3 and/or W0.sub.3 and/or As.sub.2 0.sub.3 and wherein the predominant crystal phase is selected from the group of a fluormica, a fluoramphibole, canasite, potassium and/or sodium fluorrichterite, fluorapatite, and a lithium-containing, beta-spodumene-type crystal.

Abstract: This invention is directed to the production of glass microsheet which strongly resists solarization and exhibits an ultraviolet cutoff at 370 nm, the glass consisting essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ Na.sub.2 O 6.75-7.75 B.sub.2 O.sub.3 8.75-10 K.sub.2 O 6.25-7.0 SiO.sub.2 59-63 ZnO 6.5-7.5 CeO.sub.2 4-6 Al.sub.2 O.sub.3 2-2.5 TiO.sub.2 1-3 Sb.sub.2 O.sub.3 0-0.5 CeO.sub.2 + TiO.sub.

Abstract: This invention is concerned with preparing fixed partial dentures consisting of abutment crowns and pontics connected through male/female attachments and being sealed together by means of a joining medium. In the most preferred embodiment, the parts of the dentures are formed from machinable glass-ceramic materials and the joining medium is curable through exposure to visible light radiation.

Abstract: This invention is concerned with a glass for optical and/or ophthalmic applications having an index of refraction between about 1.78-1.82, an Abbe number greater or equal to 31, and a density less than about 3.80 g/cm.sup.3 consisting essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ SiO.sub.2 15-30 CaO 15-28 B.sub.2 O.sub.3 2-17 SrO 0-11 SiO.sub.2 + B.sub.2 O.sub.3 24-36 BaO 0-11 Al.sub.2 O.sub.3 0-6.5 MgO + CaO + 16-33 SrO + BaO Li.sub.2 O 0-5 ZnO 0-11 Na.sub.2 O 0-5 La.sub.2 O.sub.3 16-30 K.sub.2 O 0-5 ZrO.sub.2 0-10 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-6 Nb.sub.2 O.sub.5 5-26 MgO 0-6 TiO.sub.2 0-14.

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 instant invention is directed to the preparation of glass articles exhibiting excellent polarization in the infrared portion of the spectrum from glasses characterized as containing silver halide particles therein selected from the group of AgCl, AgBr, AgI. The inventive method comprises four general steps:(a) a batch for a glass containing silver and at least one halide selected from the group of chloride, bromide, and iodide is melted and the melt shaped into a glass body of a desired geometry;(b) the glass body is subjected to a heat treatment at least above the strain point but not in excess of 50.degree. C. above the softening point of the glass for a period of time adequate to cause the generation of AgCl and/or AgBr and/or AgI particles therein, said particles ranging in size between 200-5000 .ANG.;(c) the glass body is elongated under stress at temperatures above the annealing point, but below that where said glass exhibits a viscosity of about 10.sup.

Abstract: The glass-ceramic disclosed is characterized by a lithium aluminosilicate crystal phase having a very low coefficient of thermal expansion and a residual glassy phase of substantial amount and higher coefficient of expansion, usually a borosilicate or boroaluminosilicate glass. The two phases form a dilatant system wherein the thermal expansion curve changes markedly in character at a transition point in the range of 500.degree.-750.degree. C., the crystal phase dominating below that temperature and the glass phase controlling at higher temperatures.

Abstract: The instant invention is directed to the production of highly crystalline glass-ceramic articles demonstrating high intrinsic mechanical strength and toughness containing crystals of canasite and/or agrellite and/or fedorite as the predominant crystal phase. The articles have overall compositions consisting essentially, expressed in terms of weight percent on the oxide basis, of about______________________________________ SiO.sub.2 45-75 CaO 8-30 F 3.5-12 Na.sub.2 O 3-15 K.sub.2 O 0-20 Na.sub.2 O + K.sub.2 O 5-25 B.sub.2 O.sub.3 0-6 Al.sub.2 O.sub.3 0-7 ZrO.sub.

Abstract: The instant invention is concerned with the preparation of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950.degree. C. without thermal deformation and being particularly suitable for application to low carbon and titanium-stabilized stainless steels. The coatings are substantially free from alkali metal oxides and consist essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ BaO 10-60 B.sub.2 O.sub.3 5-30 SiO.sub.2 25-40 Al.sub.2 O.sub.3 0-15 CaO 0-15 MgO 10-35 ZnO 0-16 Al.sub.2 O.sub.

Abstract: This invention is directed to the preparation of transparent glasses displaying a light gray-brown tint that consist essentially, in weight percent on the oxide basis, ofSiO.sub.2 --80-82B.sub.2 O.sub.3 --11.25-12Na.sub.2 O--5.25-6Al.sub.2 O.sub.3 --1.9-2.1MnO.sub.2 --0.05-0.5NiO--0.01-0.07Cr.sub.2 O.sub.3 --0.005-0.

Abstract: This invention is directed to the production of spontaneous opal glasses which demonstrate good microwave compatibility and dense opacity when drawn as sheet. The glasses consist essentially, analyzed in weight percent of______________________________________ Na.sub.2 O 2.8 .+-. 0.2 ZnO 9.4 .+-. 0.6 B.sub.2 O.sub.3 12.9 .+-. 0.5 TiO.sub.2 0.8 .+-. 0.2 SiO.sub.

Abstract: Sodium ion conducting glasses are disclosed that have a resistivity not over 10.sup.5 ohm cm. at 300.degree., are resistant to corrosive attack by liquid sodium, resist devitrification, are resistant to moisture, and are composed essentially of soda, alumina, silica, and boric oxide. The glasses are particularly useful in forming membranes to separate electrolytes in electrochemical cells such as the sodium-sulfur battery.

Abstract: The present invention is concerned with the production of photochromic glass compositions consisting essentially, expressed in terms of weight percent on the oxide basis, as calculated from the batch, of______________________________________ SiO.sub.2 52-59 B.sub.2 O.sub.3 18-23 Al.sub.2 O.sub.3 6-8 Li.sub.2 O 1-2.5 Na.sub.2 O 1-3 K.sub.2 O 8-13 ZrO.sub.2 2-6 TiO.sub.2 0-3 ______________________________________and containing, as analyzed in weight percent, of ______________________________________ Ag 0.17-0.22 CuO 0.012-0.019 Cl 0.29-0.35 Br 0.06-0.12 PbO 0.1-0.15 ______________________________________exhibiting, in 0.4 mm cross section, a clear luminous transmittance in excess of 90%, a darkened luminous transmittance below about 45% at a temperature of 25.degree. C., a darkened luminous transmittance below about 57% at a temperature of 40.degree. C., and a half fading time at both temperatures of about five minutes.

Abstract: This invention is directed to the production of fused silica-containing glass articles of large cross section or diameter wherein at least a surface layer thereof exhibits very high optical quality. The method involves depositing via flame hydrolysis/oxidation reaction a layer of fused silica-containing soot onto a supporting bait, essentially immediately thereafter applying a source of heat concentrated uniformly across the breadth of the soot deposit, but focused only over a relatively small area thereof, to raise the temperature within that area sufficiently to uniformly consolidate the soot in that area into a non-porous glass, and then cooling the glass to room temperature.

Abstract: The present invention is directed to the production of essentially dry alkali metal (R.sup.1) aluminofluorophosphate glasses optionally containing at least one divalent metal (R.sup.2) which exhibits a transition temperature below about 350.degree. C., good chemical durability, resistance to weathering, and glass stability, and which demonstrate the capability of being molded at temperatures below 400.degree. C. into complex shapes. The alkali metal aluminofluorophosphate glasses consist essentially, as analyzed on an atomic basis, between about R.sup.1 AlP.sub.2 F.sub.2 O.sub.6 and R.sup.1 .sub.3.75 AlP.sub.3 F.sub.4 O.sub.9 with the requirement that the components comply with the following atomic ratios:F:Al >2 but <4 (preferred 3.+-.0.5)P:Al >2 but <3R.sup.1 :P >0.5 but <1.24 (preferred >0.75 but <1.1)Those values, expressed in terms of weight percent as analyzed on the oxide basis, convert to the following approximate ranges:R.sup.1.sub.2 O 13-38Al.sub.2 O.sub.3 16-23P.sub.2 O.sub.

Abstract: Spurious a.c. noise signals impressed upon an electrochemical reference electrode 3 with separate half-cell and junction electrolytes are reduced by a low impedance bypass circuit including a capacitor 25 connected in series between the electrode lead wire 15 and an inert electronic conductor, such as a graphite rod 27, immersed in the junction electrolyte solution.

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.

Abstract: The present invention is directed to the production of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950.degree. C. without thermal deformation and being especially suitable for application to titanium-stabilized stainless steels. The coatings are highly crystalline, substantially free from alkali metal oxides, and consist essentially, by weight, of:______________________________________ MgO 5-35 CaO 0-35 ZnO 0-25 CaO + ZnO 10-35 Al.sub.2 O.sub.3 0-10 B.sub.2 O.sub.3 0-25 P.sub.2 O.sub.5 0-10 B.sub.2 O.sub.3 + P.sub.2 O.sub.5 4-25 SiO.sub.

Abstract: The instant invention is directed to the production of photochromic glasses having compositions consisting essentially, as analyzed in weight percent on the oxide basis, ofSiO.sub.2 --55-60Al.sub.2 O.sub.3 --9-10B.sub.2 O.sub.3 --19-20.5Li.sub.2 O--2-2.5Na.sub.2 O--2-3K.sub.2 O--6-7PbO--0.1-0.25Ag--0.1-0.15Cl--0.3-0.5Br--0.05-0.15CuO--0.0065-0.01The glasses are capable of being drawn into sheet and articles cut from the sheet simultaneously shaped and photochromic properties developed therein. The glasses display a clear luminous transmittance in excess of 90% when free from tint, a darkened luminous transmittance at 20.degree. C. below 25% when free from tint, and a fading rate at 20.degree. C. such that the glass demonstrates a faded luminous transmittance at least twice that of the darkened transmittance after a five-minute fading interval.