Spectroscopic interpretation on the UV-sensitivity of a spiroxazine-dispersed polymeric thin-film

We investigated the characteristics of a UV-sensitive naphthoxazinespiroindoline dye dispersed polymeric thin-film. Its UV absorption spectra indicate that this polymeric thin-film is suitable for the application of a ground level UV detection since its color changes in the visible range (λmax=587 nm) is proportional to UV radiation intensity. In order to evaluate the physical quantity of photochromic change by UV radiation, the waveguide method was used. The photochromic waveguide experiment shows a linear change in absorbance as UV intensity increases in the range of 1-4 mW. Based on the photoisomerization rate equation, the sensitivity of the photochromic waveguide is analytically discussed. These results might be useful for design and optimization of UV detectors using a photochromic molecule with respect to dynamic range and sensitivity