Ultrasonic velocity and attenuation in glass

Ultrasonic velocity and attenuation in glasses exhibit anomalous properties and the current theory most successful in explaining these anomalous properties in the high temperature range has been presented. The model considers that the disorder inherent in amorphous network results in a double well potential corresponding to two equilibrium configurations and a particle is ascribed to move in the double-well potential. Acoustic behaviours in glasses have been interpreted in terms of a thermally activated relaxation process. Improvement of this basic model has also been discussed. Mention has also been made of some behaviours at high temperature that need further research for convincing explanation.