Deriving a fundamental equation for macroscopic stress in chemically strengthened glass: A thermodynamic model

Traditionally, the stuffing model has been used to describe stress generation in chemically strengthened glass. Nevertheless, the associated unrealistic conditions, including an imaginary volume expansion and its suppression in an adiabatic closed system, inhibit a thorough understanding of the process. In this study, we propose a thermodynamic model in an isothermal open system to enable ion exchange without an imaginary volume expansion. We derive a fundamental equation and verify it using atomistic images obtained by Raman spectroscopy and nuclear magnetic resonance. This study paves the way for further atomistic design and development of strengthened glasses.