Fast relaxation in simple glasses as revealed by quasi-elastic light scattering.

The broad-band light scattering spectroscopy was used to investigate the relaxation processes in some molecular glasses and glassy polymers in GHz-THz spectral range from low temperatures ( 10 -50 K) up to the glass transition temperature Tg. The analysis of the data is performed and the possible mechanisms of the fast relaxation are discussed. In particular, the light scattering spectra revealed the constant loss contribution in 1 GHz to a few tenths GHz frequency range in all molecular glasses studied; it increases exponentially with temperature.