Ion-exchange diffusion kinetics and compressive stress analysis of float soda lime silicate glasses

The relationship between diffusion kinetics (interdiffusion coefficients, effective diffusion coefficients and activation energy) of the ion-exchanged float soda lime silicate (SLS) glass in the air and tin surfaces were determined by the Boltzmann-Matano and Green's function. The compressive stresses generated by ion exchange were discussed from a different viewpoint that compressive stress depth profile gradient (CSG) measurements were performed on both surfaces and analysed in symmetrical depths using FSM 6000LE surface stress metre. This method is easy, practical and non-destructive compared to other methods. Thus, this technical method will importantly result in distinguishing the compressive stress difference of symmetrical depths between air and tin surfaces. The interrelationship among the concentration profiles, CSG and diffusion kinetics of ion-exchanged glasses were evaluated. The results showed that the K+ ion concentration was increased with temperature and time and was always higher on the air surface. Results found will provide a simple guideline for both the process control and the flatness of large-area glasses in strengthening of ion-exchanged SLS float glasses.