Abstract.

We investigate the component dynamics in asymmetric binary glass formers. Focusing on the dielectric spectra of the high-T_g components m-tricresyl phosphate and quinaldine mixed with toluene as low-T_g component, the broadend spectra cannot be described by Kohlrausch or Cole-Davidson (CD) functions. Instead, we apply a generalized CD function which allows to control the width of the susceptibility independently of its high-frequency flank. The spectra show a common broadening and failure of the frequency-temperature superposition with increasing toluene concentration. This is confirmed by stimulated echo experiments showing an increased stretching of the probed orientational correlation function. In analogy to the definition of T_g, we consider “isodynamic points”. For each component, a different but linear concentration dependence of 1/T_iso is revealed, indicating different time scales. Qualitativly, we do not find significant differences for the present mixtures with T_g-contrasts of 63-89K compared to those with larger T_g-contrast ( \( \Delta T_g > 170\) K): Whereas the high-T_g component shows relaxation features similar to those of neat glass formers, yet, with “atypical” weak relaxation broadening, the faster low-T_g component displays pronounced dynamic heterogeneities. This is supported by scrutinizing NMR relaxation data of several mixtures investigated previously as a function of concentration. A universal evolution of the dynamics of the high-T_g as well as the low-T_g component is suggested for mixtures with high \(\Delta\)T_g .

Graphical abstract

中文翻译：

---

动态非对称二元玻璃形成物通过介电和NMR光谱研究。

摘要。

我们研究了不对称二元玻璃成型器中的组件动力学。着眼于高T _g组分的间苯三甲酸酯磷酸和奎尼丁与甲苯混合作为低T _g组分的介电谱，宽谱不能用Kohlrausch或Cole-Davidson（CD）函数描述。取而代之的是，我们应用了广义CD函数，该函数可以独立于其高频侧面控制磁化率的宽度。光谱显示出随着甲苯浓度的增加，频率-温度叠加的共同展宽和破坏。这通过刺激的回波实验得到证实，该实验显示出所探测的取向相关函数的拉伸增加。类似于T _g的定义，我们考虑“等动力点”。对于每种成分，揭示了1 / T _iso的不同但线性的浓度依赖性，表明不同的时标。Qualitativly，我们没有发现用于本发明混合物和T显著差异_克的63-89K -contrasts相比，那些具有更大Ť_克-contrast（\（\德尔塔T_G> 170 \） K）：鉴于高-T_克组分显示出与纯玻璃成形器相似的松弛特征，但是，随着“非典型”弱松弛变宽，低T _g更快组件显示明显的动态异质性。通过检查先前研究的几种混合物的NMR弛豫数据作为浓度的函数，可以证明这一点。对于具有高\（\ Delta \）T _g的混合物，建议了高T _g和低T _g组分的动力学的普遍发展。

图形概要