Structural Similarity on Multiple Length Scales and Its Relation to Devitrification Mechanism: A Solid-State NMR Study of Alkali Diborate Glasses and Crystals

摘要: The nature of the devitrification process is a fundamental problem in glass science and governs ultimate stability glass. It hypothesized that mechanism given composition strongly correlated with extent structural similarity at intermediate-range level between crystal phase to which it transforms. However, relatively little information available test this hypothesis because lack long-range periodicity absence effective analysis methods. In work Li2O−2B2O3 (L2B) Na2O−2B2O3 (N2B) glasses, respectively exhibit homogeneous (internal) heterogeneous (surface) mechanisms, corresponding crystals were prepared comprehensively studied by using multiple solid state NMR techniques. Of those, 11B MAS MQMAS experiments applied reveal short-range order information; 7Li 23Na spin−echo decay 11B{6Li} 11B{23Na} rotational echo double resonance (REDOR) ex...