Network Rigidity and Properties ofSiO2andGeO2Glasses under Pressure

We report in situ studies of ${\mathrm{S}\mathrm{i}\mathrm{O}}_2$ glass under pressure and find that temperature-induced densification takes place in a pressure window. To explain this effect, we study how rigidity of glasses changes under pressure, with rigidity percolation affecting the dynamics of local relaxation events. We link rigidity percolation in glasses to other effects, including a large increase of crystallization temperature and logarithmic relaxation under pressure.