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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Crystallization, Nucleation and Self-Assembly

CPP 21.6: Vortrag

Montag, 16. März 2020, 16:15–16:30, ZEU 255

Intramolecular inhomogeneities during glassy densification as studied for polyalcohols by FTIR-spectroscopy — •Friedrich Kremer, Wilhelm Kossack, and Jan Gabriel — Peter Debye Institute for Soft Matter Physics, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany

The intra-molecular potentials of a series of short polyalcohols (glycerol, threitol, xylitol, sorbitol) are studied by Fourier-Transform InfraRed (FTIR) Spectroscopy far above and below the calorimetric glass transition temperature. Analyzing the temperature dependencies of specific IR absorption bands reflecting dedicated molecular moieties, enables one to unravel on an intra-molecular scale the process of glass formation. For the v(O)-H) stretching vibration with increasing temperature a pronounced red shift is observed which enables one to deduce quantitatively the change in the extension of the inter-molecular N-H*O bonds. The intra-molecular vibrations being not involved in H-bonding show in contrast an albeit weak blue shift. The relative variation oft the width oft their respective potentials can be extracted from fits based on the Morse-function. By that the characteristic signature oft he intra-molecular inhomogenieties in the glassy systems far above and below the calorimetric glass transition temperature is obtained.