GLASS PLATE TO BE TEMPERED

摘要

To provide a glass plate to be tempered, which has a low thermal expansion coefficient at relatively low temperature, and which can have a sufficiently high surface compression stress by a conventional heat tempering process, even when it is thin. A glass plate to be tempered, which contains B2O3 in a range of from 12.5 to 35 mol % in its composition, the difference [X−Y] between the total content X of compounds selected from MgO, CaO, BaO, Na2O and K2O in the composition and the content Y of B2O3 in the composition being within a range of from −5 to 10 mol %, and which is to be tempered by heating and quenching.

主权项

1. A glass plate to be tempered, which contains, as components in a glass composition, B2O3 in a range of from 12.5 to 35 mol % in the composition and contains at least one compound selected from the group consisting of MgO, CaO, BaO, Na2O and K2O, and the difference [X−Y] between the total content X of these compounds in the composition and the content Y of B2O3 in the composition being within a range of from −5 to 10 mol %, and which is to be tempered by heating and quenching.