Stable Colored and Fluorescent Patterns Derived from Photochromic Spiropyran and Photoacid Generator

Abstract

When the poly(methylmethacrylate) films containing 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole] (SP1) and N-(1,8-naphthalene dicarboximidyl)-10-camphorsulfonate (NIC) were irradiated by UV light, a salt was formed from the reaction of phenolate in the merocyanine form (the photo-product of SP1) and the photo-generated acid. The original absorption of the film at 338 nm decreased and a new absorption band appeared at 400 ∼ 500 nm due to the salt formation between the photo-generated acid and the merocyanine form of SP1. The resulting yellow films showed an orange-red emission centered around 520 nm, while the original colorless films have no fluorescence. The irradiation of film through a mask produced a finely resolved pattern and the patterned image was quite stable over several months of storage in the dark at room temperature. The photo-irradiation of the film also induced the refractive index change as large as 0.0022.

Keywords:

• patterned image
• photoacd generator
• photochromic
• spiropyran