PHOTOCHROMIC POLYSULFONES .1. SYNTHESIS OF POLYMERIC POLYSULFONE CARRYING PENDANT SPIROPYRAN AND SPIROOXAZINE GROUPS

Photochromic polysulfones were synthesized by condensation between car boxypolysulfone (degree of substitution DS = 0.74) and functional phot ochromes (spiropyrans SP and spirooxazines SO) carrying amino, spaced amino, or spaced hydroxy groups. The synthetic methods needed to find an optimal path to satisfy the requirement of maximal photochrome conc entration, maintaining sufficient chromophore mobility in the polymeri c matrix, and avoiding polymer gelation, so that suitable membrane cas ting properties were maintained. The three-step strategy of (1) preblo cking with auxiliary group (octylamide), (2) attachment of photochrome , and (3) postblocking is certainly cumbersome and suffers from partia l removal of the attached groups, yet in essence provides material tha t satisfy the demands set out.