Structural, optical and thermal properties of glass and anti-glass phases in strontium tellurite and borotellurite systems doped with europium

Abstract Glass sample of the composition: 10SrO-90TeO2 was prepared by melt-quenching technique and found to contain triangular, rectangular, and spherical shaped micro-inclusions of the average size ∼803 μm in the glassy matrix. The inclusions grow to an average size of ∼1347 μm and assume flower-like morphology upon adding 1 mol% Eu2O3 in the 10SrO-90TeO2 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% B 2O3 in the samples inhibits the growth of inclusions of anti-glass phases and forms purely amorphous samples. B2O3 significantly enhances the photoluminescence properties of Eu 3+ doped samples. Furthermore, B2O3 converts the four-fold co-ordinated Te-O structural units into three-fold co-ordinated Te-O units.