Study on the sol-gel-synthesis of glasses with novel structure

以金属醇盐为原料，采用溶胶-凝胶法制备了用传统熔融技术无法获得的成分和结构独特的玻璃。(1)锗酸盐玻璃：采用溶胶-凝胶法制备了Na_20-GeO_2和Pb0-GeO_2玻璃。用X射线径向分布函数分析、EXAFS、IR和拉曼光谱等技术研究了玻璃中Ge的结构，特别是Ge的配位状态。(2)采用溶胶凝胶法制备了Na_20-TiO_2、BaO-TiO_2、PbO-TiO_2、Nb_20_5-TiO_2和Bi20_3-TiO_2等钛酸盐玻璃。前两种玻璃中钛的配位状态分别为5倍和6倍，Ti0n多面体高度扭曲，形成…更重要的是，这些玻璃可用于非线性光学。后三种玻璃的三阶光学非线性极化率高达10^&lt；-12&gt；esu。(3)5配位Si的Li和K-glicolato络合物被热分解，得到结构独特的Li_20-或K_20-SiO_2玻璃。而Li-Si络合物得到的玻璃结构类似于相应的熔体衍生玻璃，而K-Si络合物得到的玻璃中含有少量的5重配位Si。(4)以醇铝为原料，在严格控制的水解条件下，制备了在500ﾟC左右部分转化为α-氧化铝的氧化铝凝胶。此外，当添加锂化合物作为矿化剂时，经过精心设计的锆硅醇盐的水解反应可以在800ﾟC左右生成生成ZrSiO4的ZrO2-SiO2凝胶，所有这些结果都证实了溶胶-凝胶法可以在相对较低的温度下制备出结构和成分独特或新颖的玻璃和凝胶。较少

The sol-gel method using metal alkoxides as raw materials was appliedto the preparation of glasses with unique compositions and structure which can not be achieved by the conventional melting technique. Following results were obtained.(1) Germanate glasses : The Na_20-Ge0_2 and Pb0-Ge0_2 glasses were obtainable by the sol-gel method. The structure, especially coordination state of Ge in those glasses was examined by several tchniques such as X-ray radial distribution function analyzes, EXAFS,IR and Raman spectroscopy. It was found that the amount of 6-fold coordinated Ge ions in the sol-gel-derived glasses was almost twice as large as the corresponding melt-derived glasses.(2) Titanate glasses : The Na_20-Ti0_2, Ba0-Ti0_2, PbO-TiO_2, Nb_20_5-Ti0_2, and Bi_20_3-Ti0_2 glasses with very high content of Ti0_2 were also prepared by the sol-gel method. The coordination state of Ti in the former two glasses was 5- and 6-fold, respectively, and the Ti0_n polyhedra were highly distorted, making … More these glasses usable in the nonlinear optics. The latter three glasses, really, exhibited third-order optical nonlinear susceptibility as high as 10^<-12> esu.(3) Li and K-glicolato complex of 5-fold coordinated Si was thermally decomposed to obtain Li_20- or K_20-Si0_2 glasses with unique structure. While Li-Si complex gave glasses with the structure similar to corresponding melt-derived glasses, it was considered that K-Si complex produced glasses containing a small amount of 5-fold coordinated Si.(4) Alumina gels which transformed partly to alpha-alumina around 500ﾟC was prepared from aluminum alkoxide under carefully controlled hydrolysis condition. Also, carefully designed hydrolysis reaction of Zr-and Si-alkoxides was found to lead to the Zr0_2-Si0_2 gel which produced ZrSi0_4 around 800ﾟC,when a lithium compound was added as a mineralizer.All above results have confirmed that the sol-gel method can really make glasses and gels with unique or novel structure and compositions at relatively low elevated temperatures. Less