The structural role of alkaline earth ions in oxyfluoride aluminosilicate glasses—Infrared spectroscopy study

The effect of alkaline earth ions as a function of composition of oxyfluoride aluminosilicate glass has been explored with FTIR spectroscopy. Glasses have been prepared for Al2O3/(Na2O + MeO + 3La2F6) ratio from 0.4 to 0.8 in Na2O–MeO–Al2O3–SiO2–LaF3 systems with CaO, MgO and BaO substitution, respectively. The influence of Me2+ ions on the network structure of melts has been studied. The role of F− replacing O2− ions in the glassy network has been described as well. Spectroscopic results have been compared with thermal stability of glass and tendency to LaF3 ceramization. Finally, the effect of crystallization of LaF3 as a phase of low phonon energy (∼350 cm−1) for introduction of alkaline earth ions to the glass has been considered.