Ellipsometric analysis of isothermally devitrified metallic glasses

Effects of devitrification in metallic glasses are of particular interest for their utilization in various applications as the phase transformation from amorphous to crystalline state is known to significantly change their properties. In this work, we study the effect of devitrification on the optical properties of metallic glasses using the spectroscopic ellipsometry technique. Ellipsometry measurements on isothermally crystallized samples at controlled temperatures between the glass transition temperature and the crystallization temperature revealed characteristic dependence of the complex index of refraction on the controlled devitrification temperature, suggesting an effective optical approach which can be prospectively used for characterization of structural changes during devitrification. The crystallinity of devitrified samples was verified using a combination of differential scanning calorimetry and X-ray diffraction measurements.