Compositions of silico-sodo-calcic glasses and their applications

摘要

This invention concerns a thermally stable glass composition, which comprises the following constituents in the following proportions by weight: - SiO2 45 to 68% - Al2O3 0 to 20% - ZrO2 0 to 20% - B2O3 0 to 10% - Na2O 2 to 12% - K2O 3.5 to 9% - CaO 1 to 13% - MgO 0 to 8% - the sum of the contents of the oxides SiO2, Al2O3 and ZrO2 remaining equal to or less than 70%, the sum of the oxides Al2O3 and ZrO2 being equal to or greater than 2%, the sum of the alkaline oxides Na2O and K2O being equal to or greater than 8%, said composition comprising, if desired, the oxides BaO and/or SrO in proportions such that:11%30%This glass composition may be used for the production of substrates for an emissive screen or for that of a fire-resistant pane.