Glass-Forming Dynamics of Aluminophosphate Melts Studied by Photon Correlation Spectroscopy
Glass-Forming Dynamics of Aluminophosphate Melts Studied by Photon Correlation Spectroscopy
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用光子相关光谱研究铝磷酸盐熔体的玻璃形成动力学
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
D. Sidebottom
中科院分区：
文献类型：
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作者：
Tri D Tran;D. Sidebottom
用光子相关光谱法测量了一系列磷酸铝钠熔体的动态结构因子。这些熔体组成的氧化物网络，经历了一个均匀的增加，在晶格连接（每个结构单元）从n = 2到n = 2.8的氧化铝的添加。评价了主要粘弹性松弛特性（其形状参数β和脆性m），发现脆性以与先前报道的硫属化物和磷酸钠熔体相同的方式降低。为了解释这种常见的依赖于连接，我们转向键晶格模型和模拟，表明在删除晶格约束的脆弱性和获得的过剩熵之间的直接比例。我们建议，在脆弱性与晶格连接的变化可能会被分解成两个制度。在第一个政权在卢塞恩 2.4，我们推测，m随π n π的变化是由于对熵的较弱的振动贡献。
The dynamic structure factor of a series of sodium aluminophosphate melts has been measured using photon correlation spectroscopy. These melts consist of oxide networks that undergo a uniform increase in the lattice connectivity (per structural unit) from 〈n〉 = 2 to 〈n〉 ≈ 2.8 with the addition of alumina. Characteristics of the main viscoelastic relaxation (its shape parameter β and fragility m) were evaluated and the fragility is seen to decrease in a manner identical with that reported previously for both chalcogenide and sodium phosphate melts. To explain this common dependence on connectivity, we turn to the bond lattice model and simulations that indicate a direct proportionality between fragility and the excess entropy gained in the removal of a lattice constraint. We propose that the variation in the fragility with lattice connectivity might be decomposed into two regimes. In the first regime at 〈n〉 2.4, we speculate that the variation in m with 〈n〉 results from a weaker, vibrational contribution to the entropy.