Decoupled effects of ultrasonication: Enhanced crystallization and unaffected relaxation in molecular glasses annealed below
Phys. Rev. B 113, 024114 – Published 26 January, 2026
DOI: https://doi.org/10.1103/rrsd-p1m9
Abstract
Ultrasonic vibration has been widely applied to modify the properties of glasses, yet its influence on glass relaxation remains elusive. Here, we systematically examine the effects of ultrasonic vibrations over broad frequency and amplitude ranges on an organic molecular glass, N,N-bis(3-methylphenyl)-diphenyl-benzidine, during isothermal annealing below the glass transition temperature. Calorimetric up-scan indicates that samples annealed with ultrasound exhibit a higher probability and extent of crystallization compared to those annealed without ultrasound, while their enthalpy recovery remains unchanged. These results indicate that ultrasonic vibration facilitates local structural ordering towards crystallization, through a distinct pathway without detectably affecting the relaxation process and potential-energy evolution.
