UV-sensitive indicators based on bromophenol blue and chloral hydrate dyed poly(vinyl butyral)

UV-sensitive indicators based on dyed poly(vinyl butyral) (PVB) containing acid-sensitive dye (bromophenol blue, BPB) and chloral hydrate have been developed and used successfully to measure the integrated UV irradiance. This flexible film changes colour from blue to green and finally to yellow on exposure to UV irradiation. The radiation-induced change in colour was analysed spectrophotometrically at the absorption band maxima of 421 and 601 nm. The film responds faithfully to UVA, WE and WC radiation, showing a maximum sensitivity at 200 nm. Correlations were established between the incident energy of UV radiation and the change in absorbance of BPB/PVB films at 421 and 601 nm using irradiation wavelengths of 248.5, 298.8 and 366 nm The assessment of the uncertainties, the effect of the irradiation wavelength and chloral hydrate concentration on the performance of BPB/PVB films and the post-irradiation stability in different storage conditions were investigated. (C) 1997 Elsevier Science S.A.