Optical and mechanical behavior of glass treated by ion exchange

In this work, the effect of glass ionic exchange parameters was studied. The results have shown that the optical transmission decreases as processing time increases. An increase in hardness was also found due to the occupation of the free spaces in the glass network by the exchanged potassium, which locally induces the increase of the density. The toughness of the glass was optimal when the thermochemical treatment is carried out at medium times, by compressing the surface layers. At lower times, the potassium concentration exchanged is less whereas the extended times lead to stress relaxation of induced compression. By performing a chemical etching and using the indentation technique, we followed the properties in depth. Their evolution, below the surface, is a function of diffused potassium concentration. Raman spectroscopy was used to study the variation of the microstructure of the treated glass during different immersion times. The photoelastic measurement of Vickers indentation imprints highlights the evolution of the residual stresses.