Depth analysis of a compression layer in chemically strengthened glass using depth-resolved micro-Raman spectroscopy

We performed depth analysis of a compression layer in Corning Gorilla Glass 3, one of commercialized chemically-strengthened glasses, using depth-resolved micro-Raman spectroscopy. We obtained a depth variation of Raman spectra and an ion-exchange rate of Na for K was determined by energy dispersive X-ray spectroscopy.We found that a peak position around 1100cm^-1 in the Raman spectra is shifted to higher wavenumber and the ion-exchange rate of Na for K increases with a decreasing depth when shallower than ~30μm. This correlation can be qualitatively explained as follows: compression of a TO₂ tetrahedra network (T = Si or Al) induced by the ion exchange gives rise to an increase in frequency of vibrational modes of the TO₄ tetrahedra.