Atypical behaviour of the surface hardness and the elastic modulus of a phosphate glass matrix under 193 nm laser irradiation

The effect of 193 nm excimer laser radiation on the Knoop hardness and the elastic modulus of an ultra-phosphate glass is presented here. The experimental results reveal that the glass matrix undergoes a significant softening and volume dilation process for highly accumulated energy doses, where the Knoop hardness reduces by more than 15%, while following a single photon absorption rule. Further, during the early stages of the exposure a slight hardening process is observed. Finally, the elastic modulus is correlated with respect to the measured Knoop hardness.