Aesthetic parameters/crystallite size and residual microstrain relations in Li2O-AL2O3-SiO2 ceramic system

Lithia ceramics with three Li 2 O:Al 2 O 3 :SiO 2 molar ratios 1:1:6, 1:1:8 and 1:1:10 were prepared and vitrified. The samples obtained at optimum firing conditions were selected to study the effect of developed phases including porosity on their optical properties. Spectrophotometrical analysis and applying the CIE system for total transmission including scattering and spectral reflectance were adopted. Crystallinity was defined morphologically using scanning electron microscope (SEM). The data indicated that the structure parameters being minimum crystallite size, maximum microstrain and porosity are related to SiO 2 content. The spectral behavior depended on the nature of the glassy matrix which in turn is related to the phase compositions of the ceramic and its crystallite size. Tristimulus transmittance peak values were reduced in parallel with increases SiO 2 content. Relative brightness and chromaticity revealed similarities for bodies with larger crystallite size and minimal microstrain having the lowest and highest LAS molar ratios.