Materials Research Bulletin, Vol.106, 288-295, 2018
Structural, optical and thermal properties of glass and anti-glass phases in strontium tellurite and borotellurite systems doped with europium
Glass sample of the composition: 10SrO-90TeO(2) was prepared by melt-quenching technique and found to contain triangular, rectangular, and spherical shaped micro-inclusions of the average size similar to 803 mu m in the glassy matrix. The inclusions grow to an average size of similar to 1347 mu m and assume flower-like morphology upon adding 1 mol% Eu2O3 in the 10SrO-90TeO(2) sample. X-ray diffraction studies showed that the micro-inclusions exhibit sharp peaks, but their Raman spectra have broad phonon bands that are indistinguishable or very similar to that of the glassy matrix phase. The addition of 10 mol% B2O3 in the samples inhibits the growth of inclusions of anti glass phases and forms purely amorphous samples. B2O3 significantly enhances the photoluminescence properties of Eu3+ doped samples. Furthermore, B2O3 converts the four-fold co-ordinated Te-O structural units into three-fold co-ordinated Te-O units.
Keywords:Tellurite glasses and anti-glasses;Thermal properties;Te-O and B-O co-ordination;Raman spectroscopy;Rare-earth ions photo-luminescence;B-11 MAS-NMR