Atomic Structure and Modifiers Clustering in Silicate Glasses: Effect of Modifier Cations
Plain Language Summary
Researchers used computer simulations to study how different chemical ingredients called 'modifiers' affect the internal structure of glass at the atomic level. They found that the tendency of these modifier atoms to clump together depends on two key factors: the size of the modifier atom and how strongly it bonds to oxygen atoms in the glass network. These findings help explain why some glasses are more prone to separating into distinct regions at the microscopic scale, almost like oil and water separating in a liquid. Understanding this behavior matters because it could help scientists and engineers design better glasses with more precisely controlled properties, useful in everything from fiber optics to medical devices.
Abstract
Oxide glasses are made of a network of glass former polyhedra, and modifiers which have a role in neutralizing the charge of the glass former polyhedra or depolymerize the glass network. The effect of the modifier content on the structure and properties of the glass are to some extent, well known. However, the effect of the type of modifiers on the clustering and the tendency to form a phase separation in the glass is not investigated in detail and still not fully understood until now. Here, we use molecular dynamics to investigate the effect of the modifier type on the structure and the clustering tendency of a series of modified silicate glasses. Specifically, we show that the tendency of modifier-modifier cluster formation is linked to the modifier size and modifier-oxygen bond strength. The effect of different modifiers on the short- and medium-range structure of the glass is also discussed. This allows us to get an overview of the effect of cations nature on the properties of the glass and opens a new window for further development and optimization of the glass properties.