Atomistic simulation of nanoscale phase separation in borosilicate glass melts

Liquid–liquid phase separation in borosilicate glass significantly influences its mechanical, optical, and thermal properties, as seen in glasses like Pyrex. This study investigates nanometer-sized phase separation in Na_0.5Ca_0.25BSiO₄ (BNC25) borosilicate glass using a hybrid Monte Carlo/molecular dynamics simulation approach, focusing on thermodynamic and structural properties. Phase separation in BNC25 is thermodynamically favorable, as indicated by the positive mixing enthalpy before the simulation and the enthalpy difference before and after the simulation. We analyze changes in structural features such as coordination number, radial distribution function, and network connectivity due to phase separation and as a function of temperature.