ON THE NATURE OF PHOTOINDUCED OPTICAL ANISOTROPY IN DIACETYLENE LANGMUIR-BLODGETT-FILMS

For the first time photoinduced molecular reorientation has been obser ved in diacetylene Langmuir-Blodgett films. The compound does not show photochemical reactions of trans-cis isomerisation, and the observed phenomenon of photoinduced optical anisotropy (POA) cannot be associat ed with photoinduced trans-cis transitions as it is usually considered in viscous dye solutions and polymer films. A change in an interactio n energy for excited molecules and local recrystallization as possible reasons of the photoinduced molecular reorientation are discussed.