Photoresponsive properties of optically active (meth)acrylic homopolymers with pendant L-lactic acid or L-alanine residues connected to 4-amino-azobenzene

The photochromic behaviour and photoisomerization kinetics of optically active homopolymers of trans-(S)-4-N-(2-methacryloyloxypropanoyl)aminoazobenzene and trans-(S)-4-N-(2-acryloyloxypropanoyl)aminoazobenzene were studied by u.v. spectroscopy under irradiation at 366 nm. The resulting data are compared with those obtained for the corresponding low molecular weight structural models trans-(S)-4-N-(2-pivaloyloxypropanoyl)aminoazobenzene and trans-(S)-4-N-(2-isobutyroyloxypropanoyl)aminoazobenzene. The photoresponsive behaviour of the above polymeric systems was also investigated by circular dichroism measurements at various extents of photoisomerization. The results are discussed in terms of the structural requirements of the macromolecules