Summary and further Research

This work presents a concept for evaluating optical anisotropy effects in tempered architectural glass. The strength-increasing manufacturing process of tempered glass is achieved by creating a residual stress state with compressive stresses at the surfaces and tensile stresses in the core. Unnatural and natural disturbances in the tempering process create residual stress differences, which cause artificial birefringence. Under partially polarized daylight, it can lead to perceptible interference color patterns (anisotropy effects) after installation in the building envelope. For this purpose, a common basis of necessary fundamentals from mechanics, optics, and photoelasticity is first prepared to present the primary relationships. In particular, in photoelasticity, which is essential here, the differences between linear and circular polariscopes and their effects on direction-independent measurement are illustrated and discussed.