Medium range structure and dynamics of glass and molten glass

本文用x射线衍射对高温（~ 1600℃）玻璃熔体进行了结构分析。首先，详细介绍了x射线径向分布函数（RDF）分析的原理和步骤。其次，详细介绍了用对函数法和分子动力学（MD）计算法解释得到的实验RDF数据时的优点。本文介绍了所使用的x射线衍射仪，特别强调了为了获得高分辨率的RDF曲线，应该使用具有高能量分辨率的光子计数器，如Si（Li）固态探测器（SSD）。所得结果如下：首先，在UNIX机器Sun Ultra 5工作站上，用c语言编写了能够处理原始数据和计算RDF曲线的通用计算机程序。任何想要使用这些程序的人都可以按需使用它们。其次，对商用绿色玻璃板的模型玻璃SLS（16Na_2O 10CaO 74SiO_2）玻璃进行了结构分析，验证了所开发的程序。得到了一个分辨良好的室温玻璃的RDF曲线。每个峰对应于相应的原子对：0.164 nm处的Si-O、0.23 nm处的Na-O、Ca-O、0.27 nm处的O-O、0.31 ~ 0.32 nm处的Si-O- si等。已经证实它们工作得很好。然后，采用类似于室温下的方法，在高温炉中分析了放置在zro_2分散Pt-10%Rh带状加热器（FKS16, Furuya Metals Co.）上的SLS玻璃熔体的结构。x射线RDF分析和MD计算表明，玻璃和熔体的结构没有明显的差异，即由SiO_4四面体组成的网状结构在熔融时基本保持不变。在这方面，目前的钠钙硅酸盐玻璃可归类为“强玻璃”。MD计算还发现，Na-O和Ca-O对产生的峰在熔化时变得非常宽并扩展到更长的距离，而Si-O键长和Si-O- si键角几乎保持不变。这一结果清楚地表明，Na^+和Ca^<2+>离子的热运动在较高温度下变得明显，导致热膨胀。可以说，钠钙硅酸盐玻璃的热膨胀主要受Na^+离子的热运动控制。少

In this study, structural analysis of glass melts at high temperatures (〜1600℃) by means of X-ray diffraction has been dealt with. First, the principle and procedures of X-ray radial distribution function (RDF) analysis are described in detail. Second, the advantages of a pair function method and a molecular dynamics (MD) calculation method are also mentioned in detail, when they are used to interpret the obtained experimental RDF data. The X-ray diffraction apparatus used in this work is stated especially emphasizing that the photon counter with a high energy resolution such as Si(Li) solid state detector (SSD) should be used in order to obtain highly resolved RDF curves.The results obtained are as follows. First, the common computer programs written in C-language which made it possible to process the raw data and to calculate the RDF curves were developed using a Sun Ultra 5 workstation which is a UNIX machine. These programs are available on demand to anyone who wants to use them. S … More econd, structure analysis has been performed on SLS(16Na_2O 10CaO 74SiO_2) glass which is a model glass of commercial green glass pane in order to check the programs developed in this work. A well-resolved RDF curve was obtained for the room-temperature glass. Each peak was assigned to corresponding atomic pairs : Si-O at 0.164 nm, Na-O, Ca-O around 0.23 nm, O-O at 0.27 nm, Si-O-Si at 0.31〜0.32 nm and so on. It has been confirmed that they work perfectly. Then, the structure of SLS glass melt placed on a ZrO_2-dispersed Pt-10%Rh ribbon-heater(FKS16, Furuya Metals Co.) was analyzed at 1500℃ using a high temperature furnace in a similar way to that of the same glass at room temperature. Both the X-ray RDF analysis and MD calculation revealed that there is no distinct structural difference between the glass and melt, in other words, the network structure consisting of SiO_4 tetrahedra remains basically unchanged on melting. In this respect, the present soda-lime silicate glass can be classified into the "strong glass". It is also found from the MD calculation that the peaks due to the Na-O and Ca-O pairs become very broad and expand to the longer distance on melting, while the Si-O bondlength and the Si-O-Si bond angle remain almost unchanged. This result clearly indicates that the thermal motion of Na^+ and Ca^<2+> ions becomes remarkable at higher temperatures, leading to the thermal expansion. We can say that the thermal expansion of soda-lime silicate glasses is mainly governed by the thermal motion of Na^+ ions. Less