Effect of high temperature treatment on mechanical properties of ion-exchanged glass

Float glass was ion exchanged in KNO₃ molten salts for 16 h and treated at 300~ 550°C for 30 min. The effect of high temperature treatment on mechanical properties of ion-exchanged glass was investigated. Strength, surface stress and distribution of K⁺ of glass before and after high temperature treatment were tested. The results show that, strength and surface stress of glasses decreases after treatment. The mechanical properties of glass are deceased significantly with the increase of temperature. The strength of glass treated at 300°C is 90% that of untreated sample, while the strength of glass treated at 550°C is that of original sample, and the surface stress of glass treated at 550°C is that of ion exchanged sample. The concentration of K⁺ at glass surface deceases. K⁺ of treated glass moves inward layer and the maximum value of K⁺ moves inward accordingly which is the main reason of the degradation of glass mechanical properties.