Tellurite glasses - Part 1. Elastic properties

Tellurite glasses (purr, binary, ternary and quaternary systems containing transition metal or rare earth oxides) are now a new type of noncrystalline solids with a lot of applications over a wide range of compositions, temperatures and frequencies. Elastic properties provide much information about the structures of solids and they are directly related to the interatomic potentials. Glasses are isotropic and have only two independent elastic constant, C11 and C44. These two parameters have been collected from the longitudinal and shear sound velocities and density of the glass. The rest of the elastic constants (bulk, Young's modulus, Poisson's ratio) could be deduced. The hydrostatic and uniaxial pressure dependences of ultrasonic waves in these glasses at room temperature have been collected. The data proved both second and third order elastic constants of the glass and in consequence the shear and the longitudinal acoustic mode Gruneisen parameters have both been collected. The estimated bulk modulus and Poisson's ratio have been calculated using the bond compression model according to the cation-anion bond of each oxide present in the glass. Information about the structure of the glass can be deduced after calculating the number of network bonds per unit volume, the value of the average stretching force constant, the average ring size, the structure sensitivity factor and the mean cross-link density. Comparisons between the calculated end experimental elastic moduli and Poisson's ratio have been carried out. Also, the role of halogen inside the glass network has been discussed. (C) 1998 Elsevier Science S.A. All rights reserved.