Polarized fluorescence of N-salicylideneaniline formed by in situ exchange from N-benzylideneaniline side groups in photoaligned liquid crystalline copolymer films

Abstract

We have carried out systematic studies on a thermally stimulated photoinduced molecular reorientation of liquid crystalline copolymer films containing N-benzylideneaniline (NBA) derivative side groups, where the axis-selective trans-cis-trans photoisomerization of NBA generates molecular reorientation. The NBA derivatives in photoaligned liquid crystalline (LC) copolymer films could be hydrolyzed with maintaining molecular orientation when the hydrolyzed films exhibit the LC characterristics. N-salicylideneaniline (SA) derivates were formed by introducing various aldehyde with hydroxy group into the films using in situ reaction. SA derivates phototautomerize due to excited state intramolecular proton transfer (ESIPT) by irradiated with UV light and exhibit fluorescence. Using this fluorescence, we tried to convert to polarizing light emitting films.