The investigation of phase separation and crystallization in new heavy metal fluoride glasses

The liquid-liquid phase separation and crystallization in ZrF4-FeF3-PbF2-YF3 glasses was examined in detail by utilizing SEM, XRD, ESR, NMR and Raman techniques. The phase separation is observed from the SEM micrographs and Raman spectra of glasses respectively. The liquid-liquid phase separation was found to be the precursor to the crystallization of glass. The XRD data of the devitrified glasses show that the major crystalline phase is Pb5Fe3F19 or its distorted phase and a minor crystalline phase, PbZrF6. The ESR and NMR measurements also yielded evidence of the glass crystallization. 8 refs.; 8 figs