摘要
用多种NMR方法，包括(29)Si、(23)Na、(11)BMAS及(29)SiCP／MASNMR，研究了一定组成的Na2O－B2O3-SiO2三元体系玻璃在不同温度下分相处理24小时及用酸侵析处理后的结构变化．结果表明，在低于分相上限临界温度的范围内，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，距平衡态愈远，分相愈不完全．超过这一温度，分相可达平衡态，受热力学控制，温度愈高，混溶程度愈大．故在此温度点分相处理，可达最佳分相效果．不同校所得的NMR结果之间有良好的对应关系．
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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1997年第6期525-531,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金
