Raman, DSC, ESR and optical properties of lithium cadmium zinc tellurite glasses

The glasses with composition 64TeO(2)-15ZnO-(20-x)CdO-xLi(2)O-1V(2)O(5) (0 <= x <= 20 mol%) were prepared by conventional melt quenching technique. X-ray diffraction was used to confirm the amorphous nature. The optical absorption studies revealed that the cut-off wavelength decreases while optical energy gap (E-opt) and Urbach energy (Delta(E)) values increase with an increase of Li2O. Refractive index (n) evaluated from E-opt was found to decrease with increase of Li2O content. The physical parameters such as density (rho), molar volume (V-m) and oxygen packing density (OPD) have been analyzed and discussed. The electron paramagnetic resonance (EPR) spectra of VO2+ glasses have been recorded on X-band (v = 9.14 GHz) at room temperature. The spin Hamiltonian parameters of VO2+ ions have been calculated. It has been found that V4+ ions in these glasses exist as VO2+ in octahedral coordination with a tetragonal distortion. Raman spectroscopic studies showed that the glass network consists of TeO4, TeO3+1/TeO3 and ZnO4 units as basic structural units. The glass transition temperature (T-g) onset crystallization (T-o) and thermal stability (Delta T) were determined from Differential Scanning Calorimetry (DSC). (C) 2014 Published by Elsevier B.V.