钠硼硅酸盐玻璃分相及浸析的NMR研究

用多种ＮＭＲ方法，包括＾２９Ｓｉ、＾２３Ｎａ，＾１１Ｂ ＭａＳ及＾２９Ｓｉ ＣＰ／ＭＡＳ ＮＭＲ，研究了一定组成的ａ２Ｏ－Ｂ２Ｏ３－ＳｉＯ２三元体系玻璃在不同温度下分相处理２４小时及用酸浸析处理后的结构变化。结果表明，在低于分相上界临界温度的范围内，存在着一个温度转折点，低于这一温度时，受动力学因素影响，分相未达平衡态，温度愈低，距平衡态愈过，分相愈下完全。超过这一温度，分相可达平衡态，受热力学控

Phase Separation and Acid Etching of Sodium Borosilicate Glasses Studied by NMR

Multinuclear solid-state NMR,including 29Si 23Na 11B MAS and 29Si CP/MAS NMR was employed to study the structure change of Na2O-B2O3-SiO2 glasses after 24 hour heat-treatment of phase separation at different temperatures. Then the glasses were etched with acid.The results show that there is a turning point temperature. Being confined by dynamical fac-tors, phase separation did not reach equilibrium below this temperature. The degrec of phase separation was reduced when the temperature was decreased. When the temperature was above this turning temperature,the phase separation could reach equilibrium. Being controlled by thermodynamics,the degree of ntiscibility was enhanced when the temperature was increased.The phase separation was the best when the heat-treatment of phase separation was proceeded at this turning temperature. The NMR results obtained from different resonant nuclei were consistent with one another.