Recent crucial discoveries and perspectives on crystal nucleation in supercooled liquids and oxide glasses

Due to their measurable crystallization kinetics, oxide glass-formers are adequate systems for evaluating theoretical approaches to describe and predict crystal nucleation dynamics and mechanisms. Also, their controlled crystallization can result in glass-ceramics materials with an unusually favorable combination of properties. Therefore, understanding the crystal nucleation process in these systems has motivated extensive research efforts and a consequent boom in recent techno-scientific research that urges an update on the state-of-the-art in this topic. Accordingly, this review paper aims to provide a modern guide to the fundamental concepts and advances in the knowledge of crystal nucleation in oxide glasses and supercooled liquids in the past two decades. The discussions involve classical and non-classical approaches to describe nucleation kinetics, along with relevant discoveries associated with this process in terms of liquid molecular structure, liquid-liquid phase separation, dynamic heterogeneities, metastable phase formation, and structural relaxation. Also, strategies for predicting the nucleation mechanism, non-isothermal methods for understanding crystal nucleation, nucleation in stoichiometric and non-stoichiometric glasses, the role of nucleating agents and inhibitors, and the study of nucleation dynamics through computer simulations are critically revised. Current challenges and perspectives on crystal nucleation are presented, providing a valuable guide for scientists and future research endeavors.