Estimate of the crystallization volume fraction in lithium disilicate glass-ceramics using Fourier transform infrared reflectance spectroscopy

Fourier transform infrared reflectance spectroscopy (FTIR-RS) was investigated as a potential tool for determining the volume fraction of crystals in partially-crystallized lithium disilicate (LS2) glasses. The LS2 glass samples were partially-crystallized at two temperatures, 583 °C and 595 °C, as a function of time. These temperatures were selected based on thermal analysis of LS2 glass. The FTIR spectra of the polished sample surfaces were obtained in specular reflectance mode. The volume fraction of crystals in the samples was obtained via a point-count stereology technique. A relation between FTIR-RS peak intensities and the volume fraction of crystals in the partially-crystallized LS2 glasses was then determined. This relation can provide a convenient quality control process for glass-ceramic industry.