Influence of ZrO2 on non-isothermal crystallization kinetics, structure and optical properties of calcium borosilicate glasses

The objective of the present work is to study the effect of ZrO2 on the structure, crystallization behavior and optical properties of 30SiO2-30B2O3-10Y2O3-(30-x)CaO-xZrO2 glasses using Raman, DSC and UV–visible spectroscopy, respectively prepared by melt and quench method. The optical gap is decreased with ZrO2 content except BSZ-7.5. The refractive index, optical basicity, and oxide ion polarizability are exhibited increasing trend with increasing ZrO2 content due to the conversion of bridging oxygens into non-bridging oxygens. The FTIR spectra revealed that Q1 unit of glasses increases instead of Q2 with increasing ZrO2 content. Lasocka, Kissinger and Augis-Bennette approaches are employed to study the crystallization behavior of the glasses. Various thermal parameters such as Avrami’s constant, thermal stability and fragility index are also studied to find out their possible application. In the present study, ZrO2 acts as a modifier up to 5.0 mol% and enhance bulk crystallization whereas at higher concentration (beyond 5.0 mol%), it behaves as a former and enhance surface crystallization. [Display omitted]