Relaxation phenomena in quartz glass and quartz single crystals near the surface of submicrosecond loading

The shock wave processes occurring in quartz glass and quartz single crystals loaded by a submicrosecond (about 5 x 10 to the -8th s) pressure pulse produced by a laser are investigated experimentally. It is found that the materials studied are characterized by the 'stiffness relaxation' effect, which is attributed to the nonlinear response of a material to high-velocity perturbations. It is also shown that this effect differs from material to material.