Unique dynamic crossover in supercooled x,3-dihydroxypropyl acrylate (x = 1, 2) isomers mixture

Szymon Starzonek; Aleksandra Kędzierska-Sar; Aleksandra Drozd-Rzoska; Mikołaj Szafran; Sylwester J. Rzoska

paper

Unique dynamic crossover in supercooled x,3-dihydroxypropyl acrylate (x = 1, 2) isomers mixture

arXiv:1803.03671

Abstract

The previtreous dynamics in glass forming monomer, glycerol monoacrylate (GMA), using broadband dielectric spectroscopy (BDS) was tested. Measurements revealed the clear dynamic crossover at temperature $T_{B} = 254$ K and the time scale $τ (T_{B}) = 5.4$ ns for the primary (structural) relaxation time and no hallmarks for the crossover for the DC electric conductivity $σ_{D C}$ . This result was revealed via the derivative-based and distortions-sensitive analysis $d l n H_{a} / d (1/ T)$ vs. $1/ T$ , where $H_{a}$ is for the apparent activation energy. Subsequent tests of the fractional Debye-Stokes-Einsten relation $σ_{D C} (τ_{α})^{S} = co n s t$ showed that the crossover is associated with $S = 1$ (for $T > T_{B}$ )-> $S = 0.84$ (for $T < T_{B}$ ). The crossover is associated with the emergence of the secondary beta relaxation which smoothly develops deeply into the solid amorphous phase below the glass temperature $T_{g}$ .