Moura Ramos Joaquim J, Diogo Hermínio P, Pinto Susana S
Centro de Química-Física Molecular, Complexo I, IST, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal.
J Chem Phys. 2007 Apr 14;126(14):144506. doi: 10.1063/1.2722263.
The relaxations in amorphous D-sorbitol have been studied by thermally stimulated depolarization currents during annealing at 255 K, which is 17 K below its calorimetric glass transition temperature Tg=272 K. As the glass structurally relaxes on aging, the features of the alpha relaxation and of the Johari-Goldstein (JG) relaxation change with time. For the alpha relaxation (i) the dielectric strength decreases; (ii) the activation energy decreases; and (iii) the relaxation time increases. For the JG relaxation the dielectric strength also decreases but with a different time dependence, and there is no evidence for any modification of the kinetic features of the mobility. The amplitude of response to aging is higher for the higher temperature motional components of the Johari-Goldstein relaxation compared with the lower temperature ones.
通过在255 K退火过程中的热刺激去极化电流研究了非晶态D - 山梨醇的弛豫现象，该温度比其量热玻璃化转变温度Tg = 272 K低17 K。随着玻璃在老化过程中发生结构弛豫，α弛豫和乔哈里 - 戈尔茨坦（JG）弛豫的特征随时间变化。对于α弛豫：（i）介电强度降低；（ii）活化能降低；（iii）弛豫时间增加。对于JG弛豫，介电强度也降低，但具有不同的时间依赖性，并且没有证据表明迁移率的动力学特征有任何改变。与较低温度的组分相比，乔哈里 - 戈尔茨坦弛豫中较高温度运动组分对老化的响应幅度更高。
