Photoelasticity is an experimental stress analysis method that can be applied on glass elements to obtain direct quantitative data due to the stress-induced birefringence. This paper presents several applications of photoelasticity in glass industry and research, which demonstrate the effectiveness of the method. Photoelasticity is primarily applied for the measurement of residual stresses induced by thermal tempering which increases the apparent strength of glass. Furthermore, the paper presents the application of photoelasticity for data acquisition in the research on post-tensioned structural glass beams.