Studies of some mechanical and optical properties of: (70 − x)TeO2 + 15B2O3 + 15P2O5 + xLi2O glasses

Abstract

Specimens of the glassy system: (70−x)TeO2+15B2O3+15P2O5+xLi2O, where x=5, 10, 15, 20, 25 and 30mol% were prepared by the melt-quenching. An ultrasonic pulse-echo technique was employed, at 5MHz, for measuring: the ultrasonic attenuation, longitudinal and shear wave velocities, elastic moduli, Poisson ratio, Debye temperature and hardness of the present glasses. It is found that the gradual replacement of TeO2 by Li2O in the glass matrix up to 30mol% leads to decrease the average crosslink density and rigidity of prepared samples which affects the properties, i.e., the hardness, ultrasonic wave velocities and elastic moduli are decreased, while the Poisson ratio and the ultrasonic attenuation are increased. Also, optical absorption spectra were recorded in the range, 200–800nm for these glasses. The obtained results showed that a gradual shift in the fundamental absorption edge toward longer wavelengths occurred. Values of both of the optical energy gap, Eopt, and width tails, ΔE, are determined. It is observed that Eopt is decreased and ΔE increased with the increase of Li2O in the glass matrix up to 30mol%. The compositional dependences of the above properties are discussed and correlated to the structure of tested glasses.