Nucleation and Nanometric Inhomogeneity in Niobiogermanate Glass: In-Situ Inelastic Light Scattering and TEM Studies

We performed in-situ inelastic light scattering measurement in KNbGeO5 glass with a high nucleation ability during heating in order to elucidate nanocrystallization dynamics. The results of the in-situ measurement and TEM observation revealed that nanometric heterogeneous region (∼1-2 nm) consisting of the Nb-richer phase develops, i.e., K3Nb7O19, at the temperature, in which glassy-supercooled-liquid (SCL) phase-transition occurs, i.e., precursive stage of nanocrystallization. This strongly suggests that evolution of the nanometric Nb-richer phase in the SCL phase corresponds to nucleation in the KNbGeO5 glass.