ABNORMAL BEHAVIOR IN HIGH DENSIFICATION OF GLASS UNDER HIGH PRESSURE TREATMENT AND ITS CORRELATION TO FRAGILITY CONCEPT

通过拉曼散射光谱、Eu^<3+>荧光光谱和EXAFS光谱研究了未致密化和致密化氟锆酸盐玻璃中玻璃组分阳离子周围的局域结构。根据结构分析的结果，阐明了特殊的轻压行为的机制。对SiO_2-K_2 O-CaO-SrO硅酸盐玻璃进行了永久致密化实验。用~ 3Si MAS NMR谱对结构尚未明确的反相玻璃进行了结构分析<29>。分别对离子型ZrF_4基氟化物玻璃、离子型和共价型混合氧化物玻璃以及共价型GeS_2硫化物玻璃进行了致密化实验。讨论了具有不同化学键性质和结构的玻璃的致密化行为。用拉曼散射光谱、XAFS光谱和X射线径向分布分析等方法研究了致密化GeS_2玻璃的结构。GeS_2玻璃中Ge周围的局域结构在压缩和减压过程中发生了变化，致密化过程中，是由原位KXAFS方法检查。研究了致密化GeS_2玻璃的热弛豫行为。在热弛豫分析中，发现致密化GeS_2玻璃的热弛豫过程存在快弛豫过程和慢弛豫过程。然后，每个弛豫过程的激活能估计。通过拉曼散射谱和EXAFS谱的测量研究了这两个过程中的结构弛豫。讨论了可见光吸收边红移与热弛豫引起的结构变化之间的关系。

The local structures around glass-constituent cations in the undensified and densifid fluorozirconate glasses are examined by means of Raman scattering spectroscopy, Eu^<3+> fluorescence spectroscopy, and EXAFS spectroscopy. The mechanism of peculiar ligh-pressure behavior is clarified based on the results of the structural analyses. The permanent densification experiment in SiO_2-K_2O-CaO-SrO silicate glasses is conducted. The structures of invert-composition glasses, whose structure has not been cleared yet, are clarified by ^<29>Si MAS NMR spectroscopy. Ionic ZrF_4-based fluoride glasses, mixed ionic and covalent SiO_2-based oxide glasses, and a covalent GeS_2 sulfide glass are employed as densification experiments. The densification behavior of glasses having different chemical-bond properties and structures is discussed. The structure of densified GeS_2 glasses is examined by means of Raman scattering spectroscopy, XAFS spectroscopy, and X-ray radial distribution analysis. The local structural-change around Ge in GeS_2 glass through compression and decompression processes, i.e., densification process, is examined by an in-situ KXAFS method. The thermal relaxation behavior of densified GeS_2 glass is examined. In the analyses of thermal relaxation the presence of two types of relaxation processes, that is, the fast and slow processes, is found in the thermal relaxation in densified GeS_2 glass. Then, the activation energies of each relaxation process is estimated. The structural relaxation during both processes is examined by the measurements of Raman scattering spectra and EXAFS spectra. The relationship between the red shift of visible absorption edge and the structural change through thermal relaxation is discussed.