Spectroscopic ellipsometry investigations of Eu-doped oxy-fluoride glass and glass-ceramics

Oxyfluoride glass-ceramics in the system SiO2–Al2O3–CaF2–EuF3 containing Eu3+-doped CaF2 nanocrystals were produced by using controlled crystallization of melt-quenched glass. X-ray diffraction and scanning electron microscopy data have revealed the formation of CaF2 nanocrystals of about 50 nm size. The Eu3+-dopant ions act as the nucleating agent necessary to initiate the crystallization process. The refractive index is higher in the glass ceramics than in the initial glass and varies as the annealing time increases. Two competitive processes are responsible for this behavior, the crystallization of the CaF2 phase and the decrease of the glass ceramic mass density.

► Ceramization of Eu-doped oxyfluoride glasses have been studied by using ellipsometry.
► The refractive index is highest in the glass ceramic and varies with the annealing.
► The refractive index is influenced by CaF2 phase crystallization and the mass density.