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The frequency dependent ultrasonic velocities (both longitudinal and shear) and attenuation in BaTiO 3 doped (80V 2 O 5 ±20PbO + x BaTiO 3 ) oxide (VPB) glasses (for x 0, 1, 5, 10, and 15 wt% of the base glass) have been measured using pulse echo overlap method at room temperature. From the measured velocity, density and attenuation, various parameters namely longitudinal, shear, bulk, and Young's moduli, Debye temperature, Poisson's ratio, acoustic impedance and microhardness of the VPB glasses were determined. All these parameters of the glasses increase with addition of BaTiO 3 content. On the other hand, attenuation decreases with addition of BaTiO 3 . The variation of these parameters with the addition of BaTiO 3 content was discussed in terms of the change in structure of the glass network. The study reveals that ultrasonic velocity and attenuation measurements have been effectively used as a tool to explore the structural changes and mechanical properties on addition of BaTiO 3 in vanadate lead glasses.

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Subject classification: 61.43.Fs; 62.65.+k; S10.15 Semiconducting vanadate lead glasses with different PbO contents have been prepared by rapid quenching technique. Ultrasonic velocities and attenuation measurements have been performed over a wide range of temperatures from 150-480 K. Elastic moduli, Debye temperature and Poisson's ratio have been obtained for different PbO contents as a function of temperature. For a fixed temperature, the composition dependence of velocities and attenuation shows a monotonic variation with the addition of PbO. Nevertheless, the elastic moduli, Debye temperature, and Poisson's ratio exhibit anomalies at 33 wt% of PbO. The observed anomalies are discussed in terms of PbO acting as a network modifier or network former depending on the PbO content. In contrast to many other glasses a linear decrease in ultrasonic velocities and elastic moduli as a function of temperature is noticed without any indication of anomalies. These dependencies will be explained in terms of the structural softening taking place in the glasses. The measured acoustic loss and attenuation as a function of temperature show anomalies between 200 and 270 K depending on the PbO content. The anomalies in attenuation have been explained in terms of a thermally activated relaxation process.