A Novel Method For Stress Evaluation In Chemically Strengthened Glass Based On Micro-Raman Spectroscopy

Chemically strengthened glass is widely used for screen protection in mobile devices, and its strengthening processes and application fields have rapidly diversified. The origin of the strength is residual compressive stress induced by ion exchange, and the stress evaluation has been performed via the photoelastic effect. However, for a deep understanding of the nature of the strength and development of stronger glasses, we need a method directly connected to atomic-scale glass structures. Here, we propose a method based on the "stuffing" effect, where we can determine the residual stress non-contactively and non-destructively with a high spatial resolution using Boson, D-1, D-2, and A(1) peaks in micro-Raman spectra. Finally, we show a plausible depth dependence of the residual stress.The strength of glass can be increased post-production by treatment with chemical processes, and such materials are used in everyday devices such as mobile phones. Here, the authors report a non-invasive method based on micro-Raman spectroscopy to analyse the compressive stress responsible for the increased strength of the treated glass.