SYNTHESIS AND CHARACTERIZATION OF POLY(THIOPHENES) FUNCTIONALIZED BY PHOTOCHROMIC SPIRONAPHTHOXAZINE GROUPS

A photochromic spironaphthoxazine group has been covalently bonded in the 3 position of thiophene (I) and in the 3' position of terthiophene (II). The electrochemical and spectroscopic properties of these compo unds have been characterized, together with their photochromic propert ies, associated with the ring opening of the naphthoxazine moiety unde r light excitation, which occurs in solution and even in the solid sta te of these compounds. Electropolymerization into spironaphthoxazine f unctionalized poly(thiophenes) is only successful with II, due to the relief of steric hindrance and electronic effects on the thiophene uni ts in this compound. The much lower photochromic properties of poly(II ) are associated with the compactness of this polymer.