Sr-induced network depolymerisation in oxyfluoride aluminosilicate glasses: An infrared spectroscopy investigation

The structural changes of the amorphous silicate network in the oxyfluoride aluminosilicate glass series was investigated as a function of SrO for CaO substitution (0.0 to 2.0 moles). Using Fourier Transform Infrared (FTIR) spectroscopy coupled with Gaussian deconvolution, this study quantifies the transition from a polymerised calcium-aluminosilicate framework to a more fragmented strontium-calcium aluminosilicate architecture. Results demonstrate a linear increase in Q 3 species and a concomitant rise in structural disorder (FWHM) and bond strengths around the silicate tetrahedra. These findings confirm that Sr 2+ acts as a much more potent network modifier than previously thought, inducing direct network depolymerisation that likely dictates the energy kinetics and thermodynamics for the subsequent crystalline phase formation.