NOVEL METHODS OF SYNTHESIS OF DITHIZONATE TYPE PHOTOCHROMIC DYES AND POLYMERS

A method is described for the preparation of photochromic dyes wherein a diazotized p-aminophenyl mercuric acetate Is coupled with various c ompounds such as bis-N,N-acetoxyethylaniline and 1-phenyl-3-methylpyra zolone. This method opens the feasibility of altering the nature of th e photochromic dye just by changing the coupling compounds. Dyes prepa red by this method have been characterized and found to be superior in many respects. Acrylic type monomers with chromophoric substituents h ave been synthesized and subjected to polymerization and copolymerizat ion with other monomers. Films cast from solution of these polymers ar e found to be superior to polymers coated or imbibed with photochromic solutions.