Thermally stimulated crystallization of (20−x)LiO2–80TeO2–xWO3 glass system

Tellurite glasses of the (20−x)LiO2–80TeO2–xWO3 system were synthesized (x=0, 5, and 10) and annealed at different temperatures, and the crystallization kinetics was studied using XRD, FTIR spectroscopy, and DSC techniques. XRD data evidenced the amorphous state of as-quenched samples, while thermally treated samples showed the growth of crystalline phases. FTIR spectroscopy was used to observe the evolution of the vibrational mode assigned to the TeO2 phases. The presence of γ-TeO2, α-TeO2, and α-Li2Te2O5 crystalline phases was observed for the sample TL, x=0, while only the first and second phases were observed for TLW5 and TLW10 samples, x=5 and 10, respectively, suggesting that WO3 enters the structure preferentially as glass former, inhibiting the growth of the phase α-Li2Te2O5.

Typical DSC thermogram for TLW glasses for different heating rates with insert graphic showing as the Tg is evaluated.Figure optionsDownload as PowerPoint slideHighlights
► The crystallization kinetics was studied using XRD, FTIR spectroscopy, and DSC techniques.
► The glass transition and maximum crystallization temperatures increase when the WO3 content in the glass composition was increased.
► The observed asymmetry of crystallization peaks suggests an overlapping of distinct crystallization phases (α- and γ-TeO2).
► The WO3 enters the structure as glass former and does not participate in the crystallization of glass.