INFRARED AND RAMAN STUDIES OF STRUCTURAL RELAXATION IN AMORPHOUS TETRACOSANE, N-C24H50

Structural relaxation in amorphous tetracosane n-C24H50 was studied by infrared and Raman spectroscopies. Samples were prepared by vacuum de position onto cold substrates and the spectral changes were monitored as the temperature was raised stepwise. Several distinguishable relaxa tion processes were found to take place similarly to the case of amorp hous states of other hydrocarbons. However, in contrast to the previou s study, we arrived at a conclusion that the initial relaxation of the disordered molecules does not take place in a single step. In the lat er part of the relaxation, metastable orthorhombic-type subcells were found to appear. They disappear finally when the adjustment of the mut ual position of extended molecules occurs to attain the lateral molecu lar packing of the stable triclinic crystal. The intermolecular intera ctions along the chain direction are also discussed.