Structural characterisation of transparent oxyfluoride glass-ceramics

Erbium doped transparent glass-ceramics were obtained in the family (50GeO( 2)[50-y]PbO, yPbF(2)+xErF(3)). With controlled crystallisation of glasses b y inhomogeneous nucleation and growth during reheating, PbF2 crystallites o f nanometric size and a filling factor of 10(-2) were obtained. The phase s eparation process was studied by thermal analysis, X-ray diffraction and Tr ansmission Electron Microscopy as a function of the precursor glass composi tion and thermal treatments. The Raman spectra were also measured. (C) 2000 Kluwer Academic Publishers.