PHOTOCHROMIC POLYSULFONES .2. PHOTOCHROMIC PROPERTIES OF POLYMERIC POLYSULFONE CARRYING PENDANT SPIROPYRAN AND SPIROOXAZINE GROUPS

Photochromes, bound to polysulfone via carboxyamide bonds and physical ly blended in a polymeric matrix, were prepared and their physical and photochromic properties investigated. In order to express the photoch romic activity, plasticization is required; this is readily achieved b y using the swelling solvent, N-methylpyrrolidone (NMP). The photochro mic activity is repressed in the presence of carboxylic groups, and th is requires complex blocking of any acidity, e.g., by esterification o r amidation. The photochromic activity was expressed in membranes made from functional and blended polysulfones, yet the photoresponsive mem branes did not produce a significant electroresponse or, if they did, this decayed rapidly. Obviously, membranes with a much higher degree o f covalent binding are needed.