Preparation and structural studies in the (70 − x)TeO2–20WO3–10Li2O–xLn2O3 glasses

Quaternary tellurite glass systems (70 − x)TeO2–20WO3–10Li2O–xLn2O3 where x = 0, 1, 3 and 5 mol% and Ln are La, Pr, Nd, Sm, Er and Yb, respectively, have been prepared by the melt quenching technique. Densities of the obtained glasses were measured and the molar volume was calculated. IR absorption spectra of the present glass systems were determined at room temperature over the range of wavenumbers from 400–1,600 cm−1. Raman spectra of the present glass samples were measured in the range of 30–1,030 cm−1. Density, molar volume, IR and Raman spectra of the glasses were discussed by calculating average cross-link density, packing density, theoretically calculated Poisson’s ratio and number of bonds per unit volume of the studied glasses. Also, the quantitative interpretations were based on concentration of ions per unit volume of Te, Ln and O, short distance in nanometre between ions for (Te–O) of TeO4 and TeO3 groups, (W–O) of WO4, WO6 groups and calculated wavenumber, $$ \bar{\upsilon } $$ , for TeO4 and TeO3, respectively. The average stretching force constant that present in these quaternary glasses has been calculated in order to interpret the data obtained.