CAN TWISTED INTERNAL CHARGE-TRANSFER (TICT) STATE BE FORMED IN RIGID POLYMERS

Absorption, emission and emission anisotropy spectra of 4-cyano-N,N-di methylaniline (CDMA) and 4-cyano-2,6,N,N-tetramethylaniline (CTMA) wer e investigated in poly(vinyl alcohol) (PVA) films. It was found that t he CDMA and CTMA molecules in PVA films at room temperature display ph osphorescence, the emission band of which overlaps with the longwave f luorescence band a. The low value of the emission anisotropy shows tha t in the rigid PVA matrix there are microscopic defects in the form of empty spaces in which a certain fraction of the CDMA or CTMA molecule s can attain twisted intramolecular charge-transfer states (TICT) due to rotational relaxation. The emission anisotropies in the shortwave, b, and longwave, a, fluorescence bands of CDMA in propylene glycol wer e found to be distinctly different, this indicating that the direction s of the transition moments are not parallel.