Thermal Brillouin scattering in crystalline and fused quartz from 20 to 1000°C

The frequency shift and linewidth of longitudinal Brillouin scattering lines are given in the range of 20–1000°C. In crystal quartz, the critical index of damping is found equal to 0.8 in the α-phase and 1.9 in the β-phase; approximate values of the non-critical attenuation are obtained. These results are compared with measurements of frequency shift and linewidth in fused quartz. It is shown that high-temperature attenuation is higher in the crystalline than in the vitreous phase.