Several relaxation modes present in poly(propylene glycol) monobutyl ether [PPGMBE] were explored over a wide temperature range (120–310 K) and frequency band range (10 mHz–1.0 GHz) using wideband dielectric spectroscopy. Two resolvable secondary relaxations (β- and γ-processes) were observed below T_g, along with a structural relaxation mode (α-) above T_g. The β-relaxation process was well fitted with the Cole–Cole equation and was identified as true Johari Goldstein relaxation based on an aging experiment and a coupling model prediction. The spectra for the γ-process showed asymmetric behavior below T_g, hence it was well described by the Havriliak-Negami equation and did not show any of the peculiar behavior seen with many PPG families. The T-dependences of several dielectric properties, e.g., τ_α, τ_β, τ_γ, τ_σ, and σ_dc, were thoroughly investigated. It was noticed that the T-variation of the relaxation time for the α-mode was not satisfactorily described with only one VFT equation, and the derivative plot indicated a crossover temperature of ~240 K. Our experimental findings demonstrated that a logarithmic plot of the σ_dc versus τ_α data showed nonlinear dependency and thus were expressed by the fractional Stokes-Einstein–Debye law, with a change in the exponent from ζ = −0.70 to −0.85 for high-T (>240 K) and low-T behavior (<240 K), respectively.

使用宽带介电光谱在较宽的温度范围 (120–310 K) 和频带范围 (10 mHz–1.0 GHz) 内探索了聚（丙二醇）单丁基醚 [PPGMBE] 中存在的几种弛豫模式。在T _g以下观察到两个可分辨的二次弛豫（β-和 γ-过程） ，以及在T _g以上的结构弛豫模式（α-）。β-弛豫过程与 Cole-Cole 方程非常吻合，并根据老化实验和耦合模型预测被确定为真正的 Johari Goldstein 弛豫。γ-过程的光谱显示低于T _{g的不对称行为}，因此 Havriliak-Negami 方程很好地描述了它，并且没有显示出许多 PPG 系列中出现的任何特殊行为。对多种介电特性（例如τ _α、τ _β、τ _γ、τ _σ和σ _dc ）的 T 依赖性进行了彻底研究。注意到仅用一个 VFT 方程不能令人满意地描述 α 模式的弛豫时间的 T 变化，导数图表明交叉温度约为 240 K。我们的实验结果表明，对数图σ _dc与τ _α数据显示非线性相关性，因此由分数 Stokes-Einstein-Debye 定律表示， 对于高 T (>240 K) 和低 T 行为 (<240 K)，指数从ζ = −0.70 到 −0.85 变化）， 分别。