Most studies of the mixed‐alkali effect (MAE) have focused on relating the differences between the cations to the strength of the MAE; here we examine the effect of the glass former by comparing the MAE in aluminofluorophosphate (FP) and aluminosulfofluorophosphate (FPS) glasses. The sulfate anion in the FPS series does not bond directly to the aluminophosphate network, decreasing connectivity and increasing the ionicity of the FPS glasses. The increased degrees of freedom imparted by the sulfate are evident in the single‐alkali FPS glasses, which have lower E_a, hardness, shear moduli, and Young's moduli, and higher T_g than the corresponding single‐alkali FP glasses (without sulfate). Conversely, for the mixed‐alkali FPS compositions, the sulfate's mobility is reduced by the mixed cations, resulting in a magnified MAE for the FPS series. For dynamic properties, this phenomenon is explained by reduced plasticity and slippage along ion channels, while understanding T_g and elastic properties requires examination of the shape of the sulfate's potential energy well and the resulting regions of compressive and tensile stress. We posit that glass compositions with higher plasticity, that is, less covalent bonding, will exhibit a larger MAE, but, simultaneously, sufficient conventional glass network must be present to constrain the mobile ions.

中文翻译：

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玻璃网络离子性对混合碱效应的影响

大多数关于混合碱效应（MAE）的研究都集中于将阳离子之间的差异与MAE的强度联系起来。在这里，我们通过比较铝氟磷酸盐（FP）和铝氟磷酸盐（FPS）玻璃中的MAE来检查制玻璃机的效果。FPS系列中的硫酸根阴离子不会直接键合到铝磷酸盐网络上，从而降低连接性并增加FPS玻璃的离子性。硫酸盐赋予的增加的自由度在单碱FPS玻璃中很明显，它们具有较低的E _a，硬度，剪切模量和杨氏模量以及较高的T _g比相应的单碱FP眼镜（不含硫酸盐）高。相反，对于混合碱FPS组合物，硫酸盐的迁移率因混合阳离子而降低，导致FPS系列的MAE增大。对于动态特性，此现象可通过减少可塑性和沿离子通道的滑移来解释，而了解T _g和弹性特性则需要检查硫酸盐势能的形状以及所产生的压应力和拉应力区域。我们认为，具有较高可塑性的玻璃组合物，即共价键较少，将表现出较大的MAE，但同时，必须存在足够的常规玻璃网络以限制移动离子。