Thermal characteristics, Raman spectra, optical and structural properties of TiO2-Bi2O3-B2O3-TeO2 glasses

Abstract

Abstract. Tellurite and borotellurite glasses containing Bi 2 O 3 and TiO 2 were prepared and structure-property correlations were carried out by density measurements, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Raman and UV-visible spectroscopy. Titanium tellurite glasses require high melt-cooling rates and were fabricated by splat quenching. On adding B 2 O 3 , the glass forming ability (GFA) enhances, and glasses could be synthesized at lower quenching rates. The density of glasses shows a direct correlation with molecular mass of the constituents. UV-visible studies were used to determine the optical band gap and refractive index. Raman studies found that the co-ordination number of tellurium ions with oxygen (N Te-O ) decreases with the increase in B 2 O 3 as well as Bi 2 O 3 content while, TiO 2 produce only a small decrease in N Te-O , which explains the lower GFA of titanium tellurite glasses that do not contain Bi 2 O 3 and B 2 O 3 . DSC studies show that the glass transition temperature (T g ) increases with B 2 O 3 and TiO 2 concentrations and that T g correlates well with bond enthalpy of the metal oxides.

Synthesis, thermal, structural and linear optical properties of new glasses within the TeO2-TiO2-WO3 system

“…Therefore, it seems that amorphous "rutile-like" TiO 2 -rich regions (of few nanometers) exist separately from the TeO 2 -rich network and their number increases with increasing TiO 2 content from 2.5 to 15 mol.% in TTx glasses before an extensive growth takes place via the crystallization of rutile TiO 2 at 20 mol.% detected by X-ray powder diffraction. A thorough search of the relevant literature yielded only a single and unanimously accepted structural description of the TiO 2 -containing TeO 2 -based glasses[21,24,25,48,49] (and above all, the binary TeO 2 -TiO 2 glasses[21,22,24]). This description is based on the participation of symmetric Te-O-Ti bridges in the glass network by replacing the original Te-O-Te ones.…”