Influence of ZnO content on liquid-liquid phase separation in photothermal refractive glass

At present, volume Bragg grating (VBG) is the core devices in the field of precision optical field modulation, and their performance is mainly influenced by the substrate photothermal refractive (PTR) glass. The liquid phase separation (LLPS) behavior occurring in the base glass can lead to unnecessary scattering losses and have adverse effects on the engineering applications of VBG. In recent years, many glass scientists have conducted research on the liquid-liquid phase separation (LLPS) of glass, believing that the structure of glass phase separation is related to the composition of the glass. This study used high-temperature melting method to prepare Na-Zn-Al-Si PTR glass doped with Ag, Ce, Sn and other elements through two-step heat treatment. In this experiment, the influence mechanism of ZnO on the LLPS of PTR glasses was investigated by controlling the doping amount of ZnO. Modern analysis techniques were used to investigate the mechanism of ZnO on the LLPS, the results confirm that no crystal phase is generated during the glass phase separation in this work, and doping 4 mol% ZnO is beneficial for suppressing the LLPS of PTR glasses. In addition, the introduction of Na₂O by using NaNO₃ can avoid the generation of Ag₂O and Ag₂CO₃ impurities, which is conducive to the precipitation of NaF grains.