ULTRASONIC-ATTENUATION OF TELLURITE GLASSES

Investigations are reported of the longitudinal ultrasonic attenuation in tellurite glasses containing molybdenum oxide of different concentrations 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 very well defined peak which shifts to higher temperature with increasing frequency, suggesting a kind of relaxation process. Activation energies and relaxation frequencies were calculated; the activation energy was found to increase from 0.11 to 0.139 eV with the increase of molybdenum oxide from 20 to 50 mol.%.