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一、导论玻璃具有一种独特的物理结构。泰曼(Tammann)认为:它是一种“过冷液体”,在冷却时玻璃保持着一种特有的液态结构。在没有确定的凝固温度时,玻璃的粘滞性就要升高。虽然如此,但玻璃中的离子排列与晶体基本是相同的。在石英(SiO_2)中,每一个硅阳离子均被四个氧阴离子所包围,从而形成了一个离子处于角位置的四面体。每一个氧离子仅以一价与硅阳离子键合,而其它价则自由地参与到相邻的四面体中。因此,每一个氧离子归两个四面体所有,按照石英SiO_2的分子式,硅阳离子和氧离子之间的比例为1:2。在晶体中四面体的排列也是规则的,形成了一种周期晶格。玻璃和石英在熔融状态时,每个四面体互相之间被置换,所以使品格被扭转
I. Introduction Glass has a unique physical structure. Tammann argues that it is a “subcooled liquid,” a glass that retains a characteristic liquid structure when cooled. In the absence of a definite solidification temperature, the viscosity of the glass is increased. Nevertheless, the arrangement of ions in the glass is essentially the same as that of the crystal. In quartz (SiO 2), each of the silicon cations is surrounded by four oxyanions, forming a tetrahedron with the ions at an angular position. Each oxygen ion binds to the silicon cation only in one valence, while other voids freely participate in the adjacent tetrahedron. Therefore, each oxygen ion belongs to two tetrahedrons, and the ratio between silicon cations and oxygen ions is 1: 2 according to the formula of quartz SiO 2. The arrangement of tetrahedra in the crystal is also regular, forming a periodic lattice. When the glass and quartz are melted, each tetrahedron is replaced with the other, so that the character is twisted