Evidence for Ionic Diffusion in Dynamic Light Scattering from Glass-forming Sodium Borate Melts
Evidence for Ionic Diffusion in Dynamic Light Scattering from Glass-forming Sodium Borate Melts
复制标题
玻璃形成硼酸钠熔体动态光散射中离子扩散的证据
DOI：
10.1016/j.jnoncrysol.2022.121627
复制
发表时间：
2022
影响因子：
3.5
通讯作者：
Sidebottom, D.L.
中科院分区：
文献类型：
--
作者：
Uppala, H.G.;Sidebottom, D.L.
在玻璃形成硼酸钠熔体上进行的光子相关光谱提供了在宽的时间窗口和大的温度范围内测量这些网络形成液体的动态结构因子。的动态是复杂的，包括一个非阿耳忒弥斯温度依赖性和非指数响应的扰动，这两个都是在本测量中观察到的，这两个演变与共价键的密度的变化。一个意想不到的特征是发生第二个，慢得多的松弛过程，仅在钠改性的硼酸盐与高达10摩尔%的氧化钠发展。这第二个过程似乎是由钠离子的扩散引起的，因为它们在网络中的电荷补偿位点之间进行随机离子跳跃，其时间尺度等于粘性弛豫的时间尺度。
Photon correlation spectroscopy conducted on glass-forming sodium borate melts provides a measure of the dynamic structure factor of these network-forming liquids over a broad time window and large temperature range. The dynamics are complex and include a non-Arrhenius temperature dependence and a non-exponential response to perturbations both of which are observed in the present measurements and both of which evolve with changes in the density of covalent bonds. An unexpected feature is the occurrence of a second, much slower relaxation process that develops only in the sodium-modified borates with up to 10 mol% sodium oxide. This second process appears to be caused by the diffusion of sodium ions as they undergo random ion hopping between charge-compensating sites in the network on a timescale equal to that of the viscous relaxation.