ULTRASONIC-ATTENUATION OF TELLURITE GLASSES

Investigations are reported of the longitudinal ultrasonic attenuation in tellurite glasses containing molybdenum oxide of different concent rations by using the pulse echo technique at 2, 4, 6 and 10 MHz in the temperature range 120-300 K. The results showed the presence of a ver y well defined peak which shifts to higher temperature with increasing frequency, suggesting a kind of relaxation process. Activation energi es and relaxation frequencies were calculated; the activation energy w as found to increase from 0.11 to 0.139 eV with the increase of molybd enum oxide from 20 to 50 mol.%.