Non-isothermal crystallization of LiNaGe4O9 glass

Abstract

The glass of lithium-sodium tetragermanate LiNaGe₄O₉ is crystallized on heating under the control of differential scanning calorimetry and thermal gravimetric analysis. The measurements were prepared in the temperature range 300-870 K and showed the relatively weak endothermic DSC anomaly and 40-50 K above the single exothermic peak. The endothermic anomaly observed at T_g testified to softening the glass structure whereas the exothermic peak at T_C manifested crystallization of the amorphous phase. Studying of TGA demonstrated smooth nearly linear dependences without any visible anomalies. Varying the heating rate from 1.2 up to 40 K/min resulted in noticeable increase of the characteristic temperatures T_g and T_C. Lower limit of the glass transition temperature T_g⁰ was estimated with the help of the existing model. The mechanism of the LiNaGe₄O₉ glass crystallization is discussed.