Structure and crystallization kinetics of Li2O modified sodium-phosphate glasses

• Density of glasses depends on the field strength of various cations.
• 15 mol% Li2O contained glass shows higher thermodynamic and kinetic stability.
• FTIR and Raman study confirmed the higher polymerization in 15 mol% Li2O glass.
• As Li2O increases phosphate structural units changes from Q3 → Q2 → Q1 → Q0.

Glasses of 55P2O5(45 − x)Na2OxLi2O; (5 ⩽ x ⩽ 25) are synthesized by melt-quench technique. The amorphous nature of the as-quenched sample is confirmed by X-ray powder diffraction (XRD). The glass transition (Tg) and crystallization temperatures (Tc) are evaluated under non-isothermal conditions using the differential thermal analyzer (DTA). Crystallization kinetic of present glasses is studied using Kissinger’s and Augis–Benett models. The activation energies for glass transition (Eg) and crystallization (Ec) increases up to 15 mol% of Li2O and after that decreases. 15 mol% Li2O contained glass exhibits minimum crystallization frequency, which indicates its higher thermodynamic and kinetic stability than other glasses. FTIR and Raman analysis confirmed the higher polymerization of phosphate groups in 15 mol% Li2O glass as compared to other glasses.

FTIR spectra of the 5, 10, 15, 20 and 25 mol% Li2O glasses.Figure optionsDownload as PowerPoint slide