GLASS COMPOSITION FOR TEMPERING, TEMPERED GLASS ARTICLE AND METHOD FOR PRODUCING SAME

摘要

Obtained is a tempered glass article which has excellent thermal shock resistance and excellent chemical durability. A glass composition for tempering and a tempered glass article, each of which contains, in mol% based on oxides, 80.5-94 mol% of SiO2, 0-5 mol% of Al2O3, 3-17 mol% of B2O3 and 3-16 mol% of R2O (wherein R represents one or more elements selected from the group consisting of Na and K), with the sum of the SiO2 content (s) and a double amount of the Al2O3 content (a), namely (s + 2a) being 83-94 mol% and the ratio of the number of moles (b) of B2O3 to the number of moles (m) of non-bridging oxygen, namely (b/m) being 0.5-2.