Studies of Crystallization Kinetics of Eu-doped Sodium Niobate Glass–Ceramics and Characterization of Its Microstructure, Thermal and Optical Properties

Sodium niobate (NaNbO3) crystal containing glass–ceramics (GC) doped with Eu2O3 was synthesized by a melt quenching process followed by controlled heat treatment. The crystallization kinetics of the glass was studied using data obtained from DSC studies conducted at varying heating rates. Isothermal prediction of crystallization rates through thermo kinetics software study indicated a slower crystallization rate at 700 ℃, suggesting the possibility of controlled crystallization. Ceramization heat treatment of glass was carried out by double-stage heat treatment at 650 °C for nucleation and crystal growth at varying temperatures of 700 and 800 °C for varying durations. Optical transmission and refractive indices were measured, and photoluminescence spectra were recorded for glass and heat-treated GC samples. The excitation spectra have been recorded by monitoring emission at 612 nm corresponding to the 5D0 → 7F2 transition, and an intense 395 nm excitation band corresponding to the 7F0 → 5L6 has been observed. Emission spectra were recorded by exciting the glass samples at 395 nm. Significantly, extending the heat-treatment duration to 5 h at 800 ℃ resulted in a remarkable 30-fold increase in the intensity of red emission at 616 nm compared to the base glass.