石英玻璃微观结构的新模型

A New Model for the Nano-Structure of Vitreous Silica CHENG Shangcong

石英玻璃在以二氧化硅为基体的各种玻璃中结构最简单。对石英玻璃结构的了解是进一步掌握各种硅玻璃结构的基础。最为普及的关于玻璃结构的学说是由美国科学家查里阿森1932年提出的并得到沃伦的X光散射实验数据支持的无规则网络学说。该学说认为在石英玻璃的结构中硅氧四面体是最小的结构单元,相邻的硅氧四面体是共顶点的,整体结构是一个连续的没有重复规律的三维空间网络。虽然该学说在许多材料科学的教科书中都有介绍,但是只是一个一级近似的模型。有很多实验数据显示在0.5~2 nm的范围内石英玻璃中二氧化硅四面体的排列存在着尚未确定的规则。尽管多个领域中的科学家们进行了大量的玻璃结构方面的研究,此问题至今还未解决。提出了一个新的模型来描述玻璃在该距离范围内的结构,对此科学界长期未解的难题提供了一个新的看法。描述新模型以及详细推导新模型的文章即将发表。文章的目的是简要地介绍该结构模型,希望能得到更大范围的研究人员的关注。

Vitreous silica is the simplest silicate glass. Understanding its structure is fundamental to deciphering the structure of all other silicate glasses. The most common model for the structure of vitreous silica is the continuous random network theory（ CRN）. According to the CRN theory,Si O4 tetrahedron serves as the basic building block for the silica network. These tetrahedra are randomly linked at all four corners to form a continuous 3-dimensional network. Although the original CRN model is presented in many textbooks,it has to be regarded as a first-order approximation of the glass structure. Many experimental data show that in the medium range（ about 0. 5 nm to 2 nm）,the Si O4 tetrahedra are not randomly connected,but has some unidentified ordering. In spite of intensive studies,the medium-range ordering（ MRO） in vitreous silica is still remained as an unsolved problem.Recently the author of this article proposed a new model to solve the problem. A paper that describes the model in detail has been accepted for publication. The purpose of this short article is to introduce this newly proposed model to a larger research community.