Time-resolved thermal lens investigation of glassy dynamics in supercooled liquids: Theory and experiments
Authors: Zhang P.; Gandolfi M.; Banfi F.; Glorieux C.; Liu L.
Autors Affiliation: Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, Ku Leuven, Celestijnenlaan 200D, Heverlee, B-3001, Belgium; CNR-INO, Via Branze 45, Brescia, 25123, Italy; Department of Information Engineering, University of Brescia, Via Branze 38, Brescia, 25123, Italy; Dipartimento di Matematica e Fisica, Universita Cattolica Del Sacro Cuore, Via Musei 41, Brescia, 25121, Italy; FemtoNanoOptics Group, University de Lyon, Cnrs, University Claude Bernard Lyon 1, Institut Lumiire Matiire, Villeurbanne, F-69622, France
Abstract: This work reports results on the simultaneous spectroscopy of the specific heat and thermal expansivity of glycerol by making use of a wideband time-resolved thermal lens (TL) technique. An analytical model is presented which describes TL transients in a relaxing system subjected to impulsive laser heating. Experimentally, a set of TL waveforms, from 1 ns to 20 ms, has been recorded for a glycerol sample upon supercooling, from 300 to 200 K. The satisfactory fitting of the TL signals to the model allows the assessment of relaxation strength and relaxation frequency of the two quantities up to sub-100 MHz, extending the specific heat and thermal expansion spectroscopy by nearly three and eight decades, respectively. Fragility values, extracted from the relaxation behavior of the specific heat and the thermal expansion coefficient, are found to be similar, despite a substantial difference in relaxation strength.
Journal/Review: JOURNAL OF CHEMICAL PHYSICS
Volume: 155 (7) Pages from: 074503-1 to: 074503-14
More Information: C.G. and M.G. are grateful to the KU Leuven Research Council for financial support (Grant No. C14/16/063 OPTIPROBE). L.L. acknowledges the financial support from FWO (Research Foundation-Flanders) postdoctoral research fellowship (Grant Nos. 12V4419N and 12V4422N). P.Z. acknowledges the support of the Chinese Scholarship Council (CSC). M.G. acknowledges financial support from the National Research Council Joint Laboratories program [Project No. SAC.AD002.026 (OMEN)]. F.B. acknowledges financial support from the University de Lyon in the frame of the IDEXLYON Project (No. ANR-16-IDEX-0005) and University Claude Bernard Lyon 1 through the BQR Accueil EC 2019 grant.KeyWords: heat spectroscopy; propylene-glycol; temperature lens; light-scattering; relaxationDOI: 10.1063/5.0060310