1989 年 13 巻 S_1_PMRC_89 号 p. S1_763-768
Mechanical strength of the glass substrate after chemically strengthening exhibits three modes in Weibull chart according to the distribution of internal stress embedded in the substrate surface by ion-exchange. By chemically strengthening, average fracture strength of glass substrate increases from σ =96.3MPa to σ=300-650MPa depending upon the depth of ion-exchange. Fracture probability, however fracturates from 5E10-13 to 1.5E10-38, which crosses over the fracture probability of the raw-glass (F=2.1E10-23). This paper discusses the theoritical assumption on three-mode model appeared in the Weibull chart in conjunction with experimental data.