Crystallization mechanism of Bi2Ti2O7 from 0.25Bi2O3-TiO2-0.25Na2O-SiO2 glass

We have studied the crystallization kinetics of pyrochlore Bi2Ti2O7 (BTO) from 0.25Bi(2)O(3)-TiO2-0.25Na(2)O-SiO2 (BTNSO) glass under isothermal and non-isothermal conditions. On the course of crystallization, only BTO crystal within the confined size under 100 nm is formed and the rest of the components of asquenched BTNSO glass remains as a remanent glass even at the final stage of crystallization. The crystallization mechanism of BTO belongs to a constant nucleation rate with the diffusion-controlled growth and any heterogeneous nucleation or impingement in growth is not pronounced. The change of phonon modes in the senses of energy and population for different phases enables us to get the insight of crystallization in the view of both macroscopic and microscopic points. (C) 2020 Elsevier B.V. All rights reserved.