Synthesis of new photochromic polymers based on phenoxynaphthacenequinone

Photochromic compounds of the phenorynaphthacenequinone type have been incorporated chemically in three polymers: polystyrene, poly(methyl methacrylate), and polysiloxane, overcoming grave synthetic problems due to the presence of the quinone group. Contents of up to one photochromic unit per polymer unit could be obtained without impairing the photochromism of the polymers. Interconversion of the two modifications of the photochrome takes place photochemically but not thermally and is completely reversible, both in the free and in the incorporated photochrome