Molecular dynamics study of UV-laser-induced densification of fused silica. II. Effects of laser pulse duration, pressure, and temperature, and comparison with pressure-induced densification

Numerical simulations on UV-laser-induced densification of fused silica have been performed using classical molecular dynamics. The effect of laser irradiation is modeled by the energy transfer from the absorbed laser photons to the bonded silicon and oxygen atoms, i.e., the thermal effects of laser-irradiation on silica glass. Results from simulations at various laser pulse duration, pressure, and temperature conditions show that longer laser pulse duration, higher pressure, and higher temperature cause larger densification. We have also compared the microstructural and elastic properties of fused silica densified by UV-laser and hydrostatic pressure, respectively. Similar changes are observed in both cases; several notable differences are noticed, too, and include Si–O bond length change, number of over-coordinated atoms, and ring distributions.