CHEMICALLY DURABLE, LITHIUM-FREE GLASS COMPOSITIONS

摘要

Chemically durable glass compositions are disclosed. In embodiments, the glass composition includes: 48 mol. % to 61 mol. % SiO2; 0 mol. % to 1 mol. % Al2O3; 7 mol. % to 20 mol. % B2O3; 9 mol. % to 16 mol. % R2O, where R2O is a sum of alkali oxides present in the glass composition; 9 mol. % to 15 mol. % Na2O; and 8 mol. % to 21 mol. % ZnO. The glass composition may be substantially free of Li2O. RO (mol. %)<0.5×ZnO (mol. %), where RO is a sum of the alkaline earth oxides in the glass composition. An average coefficient of thermal expansion of the glass composition is 75×10−7/° C. to 88×10−7/° C. over a temperature range from about 20° C. to about 300° C. The glass composition comprises a softening point less than or equal to 660° C. The glass composition comprises a hydrolytic resistance of class HGA1 or class HGA2 according to ISO 720:1985.