Attenuation and Velocity of Ultrasonic Waves in Amorphous Selenium in the Vicinity of the Glass Transition

Attenuation and velocity of longitudinal ultrasonic waves have been measured in a-Se in the vicinity of the glass transition. Both quantities are shown to be affected significantly by the stabilization process below the glass transition temperature Tg. Equilibrium values of sound velocity are also reported for the range 25 °C to 45 °C. The decrease (increase) of attenuation (velocity) during stabilization is reversed at higher temperatures. The connection of both quantities is discussed in terms of an effective temperature which allows the approximate determination of equilibrium values of attenuation (and possibly of other structure related properties) from measurements performed in nonequilibrium states.