High-Temperature Investigation of TeO2-Na2O-ZnO Glasses

Herein, a ternary system of TeO2-ZnO-Na2O (TZN) with competitive roles of covalent Zn-O and ionic Na-O bonds in tellurite glassy network is examined for high-temperature in situ X-ray diffraction (XRD) and Raman spectroscopy. TZN glasses are doped with Nd2O3 and the effects of Nd doping on the crystallization of glasses are also written. In situ high-temperature XRD permits the assignment of each of the differential scanning calorimetry (DSC) crystallization peaks (the first crystallization peak (T-c(1)) is related to sodium-based crystalline phases, while the second crystallization peak (T-c(2)) is correlated with tellurium-/zinc-based crystalline phases). The study of in situ high-temperature Raman spectroscopy shows that T-c1 shows gamma-TeO2 crystallized phase-like peaks while T-c2 crystallization has more alpha-TeO2-crystallized phase-like peaks. Comparison at the same temperature (430 degrees C) permits a first understanding of the structural changes of the glasses in terms of the evolution first to alpha-TeO2, ZnO, ZnTeO3, and Zn(2)Te(3)O(8 )crystalline phases compared with Na10Zn4O9 phase. The ZnTeO3 and Zn2Te3O8 crystallization evolution is also compared between the Nd-doped and nondoped glasses, which gives more insight into the tellurite glass structures.