Thermal and microstructural characterization and crystallization kinetic studies in the TeO2−B2O3 system

► The glass forming range of the system was determined as 5-25 mol% B2O3. ► The monotectic reaction: liquid1 → liquid2 + TeO2, was detected at 666 ± 2 °C. ► α-TeO2 and B2O3 phases were observed as spherical and multilayered crystallites. ► Transparent phases were rich in TeO2, while the opaque phases were rich in B2O3. ► The EA value of the crystallization reaction was calculated as around 300 kJ mol−1.