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

Autor: Aleksandra Drozd-Rzoska, Szymon Starzonek, Mikolaj Szafran, Aleksandra Kędzierska-Sar, Sylwester J. Rzoska
Rok vydání: 2018
Předmět:
Zdroj: The European Physical Journal E. 41
ISSN: 1292-895X
1292-8941
Popis: The previtreous dynamics in the glass-forming monomer, glycerol monoacrylate (GMA), was tested using the broadband dielectric spectroscopy (BDS). The measurements revealed a clear dynamic crossover at the temperature $ T_{B} = 254$ K and the time scale $ \tau (T_{B}) = 5.4$ ns for the primary (structural) relaxation time and no hallmarks for the crossover for the DC electric conductivity $\sigma_{DC}$ . This result was revealed via the derivative-based and distortions-sensitive analysis $ \mathrm{d} \ln H_{a}/\mathrm{d} (1/T)$ vs. $ 1/T$ , where $ H_{a}$ stands for the apparent activation energy. Subsequent tests of the fractional Debye-Stokes-Einsten relation $ \sigma_{DC} (\tau_{\alpha})^{S} = \mbox{const}$ showed that the crossover is associated with $ S = 1$ $ (\mathrm{for}\ T > T_{B}) \rightarrow S = 0.84$ (for $ T < T_{B}$ . The crossover coexists with the emergence of the secondary beta relaxation, which smoothly develops deeply into the solid amorphous phase below the glass temperature $ T_{g}$ .
Databáze: OpenAIRE