Multimetastability effect on the intermediate stage of phase separation in BaO- SiO2 glass

Controlling the phase separation phenomenon can enhance the properties of glass materials, such as transparency and strength. However, the initial and intermediate stages of phase separation of amorphous glass are yet to be understood completely. In this study, we performed an in situ observation on glass through scanning transmission electron microscopy, which possesses a high spatial resolution and chemical sensitivity. We visualized the phase-separated structure in the initial and intermediate stages of phase separation and observed a local and rapid change in the phase-separated structures and the formation of regions with advanced and delayed degrees of phase separation. The results were compared with the phase-field simulation and it was concluded that the characteristic change of the phase-separated structures is attributable to the multimetastability of the amorphous phase.