Tellurite glasses Part 2. Anelastic, phase separation, Debye temperature and thermal properties

The goal of the present review is to collect and analyze the dependence of the longitudinal ultrasonic attenuation with different frequencies and temp erature (below room temperature) and the elastic moduli at room temperature for tellurite glasses containing different modifiers in the binary and ter nary forms. The quantitative analysis of the experimental acoustic activati on energy has been discussed in terms of the number of loss centers (number of oxygen atoms that vibrate in the double-well potential). Also, the corr elations between the acoustic activation energy at low temperature and both bulk modulus at room temperature and mean cation-anion stretching force co nstant have been collected. The effect of radiation and the presence of non bridging oxygen atoms (NBO) on the ultrasonic attenuation and internal fric tion have been collected. Secondly, the phase separation test by using the nondestructive elastic moduli have been collected for these new noncrystall ine solids. Thirdly, the acoustic and optical Debye temperature data for te llurite glasses have been collected from the measurements of ultrasonic vel ocities (both longitudinal and shear waves) and from the theoretical calcul ations of the IR spectra of these amorphous solids. Also, the effect of gam ma-radiation on the values of acoustic Debye temperature has been collected . Fourthly, the thermal properties: glass transformation temperature T-g, g lass crystallization temperature T-c and glass melting temperature T-m and thermal expansion coefficient alpha(th) were collected. The values of glass transformation and crystallization activation energies according to differ ent models have been collected. The correlations between the thermal proper ties (T-g) with the average crosslink density and average stretching force constant have been collected. While the thermal expansion coefficient has b een collected and discussed vibrationally by correlating it with mean long wavelength acoustic mode Gruneisen parameter gamma. (C) 1999 Published by E lsevier Science S.A. All rights reserved.