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Visibly observed photocrosslinkable pendant liquid crystalline polymers containing indolyl based chalcone were synthesized by free-radical polymerization and characterized spectroscopically. The differential scanning calorimetry and polarized optical microscopy were used to examine liquid crystalline property. The photocrosslinking and luminescence properties were monitored by UV-Vis spectrophotometer and spectrofluorimeter, respectively. It demonstrates the chalcone unit did not manifest cis ↔ trans-isomerization reaction along with 2π+2π photodimerization upon irradiation with UV light like other chalcones hitherto reported. The photocrosslinking was visibly monitored in solution through change of fluorescent color to colorless. The spacer lengths play a key role in the reaction. The fluorescence maximum was blue shifted around 70 nm in chloroform solution upon irradiation with UV light confirms the 2π+2π photodimerization of chalcone unit.

Copolymer containing new thermally reversible click chemistry-assisted triazole-substituted azobenzene and fulgimide units in the pendant F-co-A was prepared by free-radical solution addition polymerization technique. The F and A were also prepared for comparison. The DSC analysis of F indicates that the polymer possessing the C-form of fulgimide unit exhibited higher Tm than that of E-form of the same polymer and revealed that the C-form of fulgimide unit in F is highly ordered. The cis-trans back isomerization behavior of the click chemistry-assisted triazole-substituted azobenzene unit in film A has thermal irreversibility, while in F-co-A it exhibited thermal reversibility. The UV-exposed film of F-co-A heated around Tg leads to cis-trans back isomerization of azobenzene unit and thermally stable C-form of fulgimide which retains its conjugated structure where both the photochromic units are converted into planar conformations and exhibit high fluorescence properties. The fluorescence maxima of C-form in F-co-A red shifted compared with F, because the substituted triazole ring in the azobenzene unit stabilized the C-form of fulgimide unit. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7843–7860, 2008