ULTRASONIC VELOCITY AND ATTENUATION IN PB-PHOSPHATE GLASS

Ultrasonic velocity and attenuation have been measured in six differen t samples of Pb-phosphate glass at a frequency of 10 MHz in the temper ature range 80 to 300 K, The velocities, both longitudinal and transve rse, increased monotonically with decreasing temperature. Temperature variation of attenuation showed a high temperature relaxation peak in each sample. The temperature dependence of the attenuation is interpre ted in terms of a thermally activated relaxation process. On the other hand, the combined effect of relaxation and anharmonicity is consider ed to explain the variation of velocity with temperature. (C) 1997 Els evier Science B.V.