Comparison between fused silica of type II and III after surface heating with a CO2 laser

We compare the effect of CO2 laser heating on silica samples of type II and III; these two materials having significant differences in composition and physical properties. For both types of silica, the crater shape and depths are similar through all the parameter ranges that were studied. This is particularly true when evaporation is the major mechanism of the crater formation process. Our numerical simulations of thermal heating are consistent with these results, and calculations with a physically based model of evaporation evaluate correctly the crater depths. Therefore, it can be conclude that the heating of silica surface by CO2 laser at temperatures sufficient to remove some material is independent of their metallic impurities and hydroxyl content, or the different values for the annealing and softening temperatures.