engleski

Structural properties of tellurite glasses

The structure of a-TeO2 polycrystalline material, TeO2 glass and crystallized beads, and xNa2O-(100-x)TeO2, (0<x<33.3) glasses have been investigated by XRD and Raman spectroscopy. In the TeO2 glass beads deformed TeO4 tbp are connected by sharing corners similarly as in a-TeO2 polycrystalline material. The Raman spectra exhibit that the structure of the xNa2O-(100-x)TeO2, (0<x<33.3) glasses is composed of both TeO4 tbp and TeO3 tp while the fraction of TeO3 tp increases with increasing Na2O content. The changes in the glass structure with increasing Na2O content are a result of Te-O-Te disruption and the formation of non-bridging oxygens (NBO). The XRD and Raman spectra for the xNa2O-(100-x)TeO2, (0<x<33.3) crystallized compositions show that the composition containing 16.7, 20.0 and 25.0 mol% Na2O crystallized to a-TeO2 and Na2Te4O9 crystalline phases. Comparing the Raman spectra of glasses and crystallized compositions containing > 20 mol% Na2O it was shown that the local structure of glasses differs from the structure of their crystalline counterparts.

Tellurite glasses; Raman spectrosopy

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