Thermal and Structural Properties of Alkali Modified TeO2 Glasses

The structural and thermal properties of lithium, sodium, and potassium tellurite glasses, written as JM2O-TeO2 where M is an alkali metal, were studied. Raman spectra were measured on all glasses along with the glass transition onset (Tg), crystallization (Tx), and melting (Tm) temperatures. All thermal measurements were measured on a Perkin-Elmer DSC-7. The thermal measurements were compared to the coordination of the tellurium. Coordination data was found by deconvoluting Raman spectra using Igor Pro to find the percent of Q4 and Q3 units in the glass.
Pure amorphous TeO2 was made using the water-quenching method then thermally tested against time to see how the glass transition onset and crystallization changed. We measured Tx and Tg every 30 minutes on glassy TeO2. Since TeO2 has a strong crystallization tendency, the samples were prepared in a nitrogen glovebox to minimize the effect that water could have on the recrystallization.