Molecular dynamics simulations of ion-exchanged glass

Abstract

Chemically strengthened glass is one of the key enablers of the modern consumer electronics industry. Molecular dynamics simulations offer an opportunity to build enhanced fundamental understanding of the ion exchange process used for chemical strengthening. In this work, we apply molecular modeling techniques to investigate several aspects of ion-exchanged glasses that are either inaccessible through experiment or too difficult to probe through experiments alone. In particular, we use atomistic modeling to study the dependence of the linear network dilation coefficient on the concentration of alkali ions exchanged. We also calculate the evolution of elastic moduli as a result of the ion exchange process. Both of these quantities—the network dilation coefficient and the Young's modulus—are critical parameters for determining the final compressive stress profile of the chemically strengthened glass. Finally, we revisit the issue of structural differences between as-melted and ion-exchanged glasses in terms of local atomic number density around alkali ions. The results of this work point to the unique structures attainable through ion exchange that cannot be achieved through melt-quenching alone.