Thermal, structural and optical properties of new TeO2Sb2O3GeO2 ternary glasses

Abstract In this work the novel glass system TeO 2 Sb 2 O 3 GeO 2 was investigated and promising glass compositions were selected for further specific studies. Glass samples in the (80-0.8x)TeO 2 -(20-0.2x)Sb 2 O 3 –xGeO 2 molar composition were prepared by the melt-quenching method with a glass-forming domain from x = 10 to x = 90. Samples were investigated by XRD, DSC, FTIR, Raman spectroscopy and UV–visible absorption. The XRD and DSC results bring informations about the non-crystalline state and thermal properties of these materials. It has been observed that higher GeO 2 contents lead to higher glass transition temperatures and thermal stabilities against crystallization. FTIR and Raman spectroscopies suggest a progressive incorporation of GeO 2 in the covalent network of TeO 2 with conversion of structural units TeO 4 to TeO 3 . Absorption spectra revealed the high visible transparency of these samples and an increase of the optical band gap with GeO 2 addition, in agreement with a decreasing polarizability of the glass network. Er 3+ doped and Er 3+ /Yb 3+ codoped samples were also studied with respect to their infrared emission properties and higher GeO 2 contents lead to an increase in IR emission intensity at 1,5 μm as well as longer radiative lifetimes. Finally, upconversion emission in the visible were also recorded and were shown to be strongly dependent of the composition.