Proceedings of SPIE 1989
Conference paper

The characterization of structural disorder in thin films at elevated temperatures by spectroscopic methods

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Changes in the IR bandshapes and shifts in frequency can provide an insight into the nature of molecular motion occurring prior to structural reorganization which accompanies a phase transition. In the case of Langmuir-Blodgett films of polymerizable molecules, often there is competition between polymerization and the occurence of structural disorder when monomeric films are subjected to elevated temperatures. To distinguish these two mechanisms, a series of melting experiments on L-B films of cadmium arachidate were under-taken using grazing incidence reflection techniques to assess the change in molecular orientation and order as a function of temperature: The spectroscopic observations being correlated with DSC measurements. Similar thermal and spectroscopic studies of octadecyl-fumarate [H(CH2)180C(0)CHCHC00]2, Cd indicated that although the resulting polymer was structurally similar to that obtained by UV irradiation at ambient temperature, the orientation of the hydrocarbon side chain and the backbone bridging group (-0C(0)CHCH-) was disrupted owing to the thermal disorder introduced prior to or at the time of polymerization. © 1985 SPIE.