ANISOTROPY OF INFRARED ABSORPTION SPECTRUM AND VISIBLE ABSORPTION OF DICHROIC DYESTUFF (CONGO RED)

Abstract

In the case of the orientation evaluation of non-crystalline region of the uni- and bi-axially stretched crystalline polymer, the evaluation of molecular orientation can be made by the measurement of the visible dichroism or the infrared dichroism. However, we have not obtained the information concerned with the dyed mechanism between the non-crystalline chain and the dye molecule. In order to explore the mechanism, a single crystal of Congo Red was prepared, and then the visible dichroism and/or the infrared spectra of the crystal were measured. By using these results, we determined the dichroism of the characteristic absorption band of the crystal.
Finally, the birefringence, infrared diohroism, orientation factor of crystalline region and crystallinity were measured for the highly stretched PVA film in which large amount of the dye were dissolved.
From the results, the angle between the non-crystalline chain and the dye molecule was determined on the basis of the additivity of birefringence.