SYNTHESIS, CHIROPTICAL PROPERTIES AND PHOTORESPONSIVE BEHAVIOR OF OPTICALLY-ACTIVE Y[(S)-4-(2-METHACRYLOYLOXYPROPANOYLOXY)AZOBENZENE]

A novel optically active monomer containing a photochromic chromophore , such as ans-(S)-4-(2methacryloyloxypropanoyloxy)azobenzene and its l ow molecular weight model compound trans-(S)-4-(2-pivaloyloxypropanoyl oxy)azobenzene were prepared. Free radically initiated homopolymerizat ion of the methacrylic monomer afforded in fairly high yield a rather high molecular weight polymer which was molecularly and structurally c haracterized. The molecular mobility of the polymer in all trans confi guration, as well as chiroptical properties, photoisomerization kineti cs and photochromic behaviour were investigated and compared with thos e of the low and high molecular weight related compounds. The polymer photoresponsive properties were evaluated by circular dichroism measur ements at various extents of photoisomerization. All the results are d iscussed in terms of structural requirements of the macromolecules. (C ) 1998 Elsevier Science Ltd. All rights reserved.