DIFFERENTIAL SCANNING CALORIMETRY, X-RAY-DIFFRACTION AND F-19 NUCLEAR-MAGNETIC-RESONANCE INVESTIGATIONS OF THE CRYSTALLIZATION OF INF3-BASED GLASSES

Results of differential scanning calometry (DSC), x-ray diffraction (X RD), and F-19 nuclear magnetic resonance (NMR) of InF3-based glasses, treated at different temperatures, ranging from glass transition tempe rature (T-g) to crystallization temperature (T-c), are reported. The m ain features of the experimental results are as follows. DSC analysis emphasizes several steps in the crystallization process. Heat treatmen t at temperatures above T-g enhances the nucleation of the first growi ng phases but has little influence on the following ones. XRD results show that several crystalline phases are formed, with solid state tran sitions when heated above 680 K, The F-19 NMR results show that the sp in-lattice relaxation, for the glass samples heat treated above 638 K, is described by two time constants. For samples treated below this te mperature a single time constant T-1 was observed. Measurements of the F-19 spin-lattice relaxation time (T-1), as a function of temperature ,made possible the identification of the mobile fluoride ions. The act ivation energy, for the ionic motion, in samples treated at crystalliz ation temperature was found to be 0.18 +/- 0.01 eV. (C) 1998 American Institute of Physics.