Crystallization of Tungstenbronze Phase and its Inelastic Light Scattering in Niobiophosphate-System Glass

We prepared a niobiophosphate-glass-crystallizing tungstenbronze-type Ba2NaNb5O15and measured elastic light scattering spectrain situin the glass-ceramics fabrication regime. We found that the studied glass possesses a strong tendency for phase separation into Al2O3P2O5and Nb-rich regions prior to crystallization. It is suggested that the tungstenbronze phase crystallizes in the Nb-rich region separated from the supercooled liquid phase. This study demonstrated thatin situRaman spectroscopy is also useful for observing the phase separation dynamics in glass.