Abstract: Glass, for encapsulating a semiconductor, which is substantially free of lead or other harmful ingredients, but which exhibits a sealing temperature of not higher than 710° C., and which stably seals with Dumet. Further, when the glass has a viscosity of 106 dPa·s, the temperature of said glass is not higher than 710° C., and includes two or more of Li2O, Na2O and K2O and B2O3. Also, the glass may comprise: SiO2, B2O3 and Al2O3 in an amount of from 40 to 70%, from 5 to 20% and from 0 to 15% by weight, respectively; MgO, CaO, SrO, BaO and ZnO in a total amount of from 0 to 45% by weight; and Li2O, Na2O and K2O in a total amount of from 5 to 25% by weight.

Abstract: A glass composition for glass bubbles used as reinforcing fillers in plastic resin articles has an improved compressive strength and the reduced alkali amount leached from the glass. The glass composition consists essentially of, by weight percentages, SiO.sub.2 40-59%, R.sub.2 O 2-17%, R.sub.2 O being at least one selected from Li.sub.2 O, Na.sub.2 O, and K.sub.2 O, B.sub.2 O.sub.3 1-25%, RO 5-25%, RO being at least one selected from CaO, MgO, BaO, ZnO, and SrO, RO.sub.2 6-40%, RO.sub.2 being at least one selected from TiO.sub.2 and ZrO.sub.2, Al.sub.2 O.sub.3 0-13%, P.sub.2 O.sub.5 0-3%, and SO.sub.3 0.1-1.0%.

Abstract: A sealing composition suitable for sealing alumina packages for integrated circuits at a temperature below about 450.degree. C. for a short time of about 10 minutes. The composition is a mixture of 50-80 wt. % vitreous solder glass powder of PbO-B.sub.2 O.sub.3 system having a deformation point of 350.degree. C. or less, 1-35 wt. % first ceramic powder and 1-45 wt. % second ceramic powder. The total amount of the first and second ceramic powders is 20-50 wt. %. The first ceramic comprises 68-75 wt. % ZnO, 23-28 wt. % SiO.sub.2 and 0-8 wt. % Al.sub.2 O.sub.3, and the second ceramic comprises 98-99.9 wt. % SnO.sub.2 and 0.1-2 wt. % ZnO.

Abstract: An alkali resistant glass composition comprising the following oxides in a weight percentage composition of 57 - 64% SiO.sub.2, 19 - 23.5% ZrO.sub.2, 0.5 - 2.5% Li.sub.2 O, 11 - 18% Na.sub.2 O, 0 - 6% K.sub.2 O, 0 - 0.5% RO, 0 - 0.5% Al.sub.2 O.sub.3 and 0 - 0.5% M.sub.x O.sub.y wherein R is an alkaline earth metal, M is a metal other than an alkaline earth metal, and x and y are positive integers where (valence of M) multiplied by x = 2y, and satisfying the relationships defined by following expressions (1) and (2):21 .gtoreq. Na.sub.2 O + Li.sub.2 O + K.sub.2 O.gtoreq. 15.5 (1)52 - 2zr.sub.2 O.gtoreq.4Li.sub.2 O - K.sub.2 O.gtoreq.ZrO.sub.2 - 21 (2);and alkali resistant glass fibers prepared therefrom.

Abstract: Glass compositions of the SiO.sub.2 -ZrO.sub.2 -alkali metal oxide-alkaline earth oxide system containing 70-82 mole percent SiO.sub.2 and 2-8 mole percent ZrO.sub.2 and alkali metal oxides and alkaline earth oxides, and optionally Al.sub.2 O.sub.3, in specified amounts, such glasses being resistant to water, acids and alkalies, having a low to medium thermal coefficient of expansion and a low liquidus temperature.