UV-SENSITIVE INDICATORS BASED ON BROMOPHENOL BLUE AND CHLORAL HYDRATEDYED POLY(VINYL BUTYRAL)

UV-sensitive indicators based on dyed poly(vinyl butyral) (PVB) contai ning acid-sensitive dye (bromophenol blue, BPB) and chloral hydrate ha ve been developed and used successfully to measure the integrated UV i rradiance. This flexible film changes colour from blue to green and fi nally to yellow on exposure to UV irradiation. The radiation-induced c hange 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. Correlatio ns were established between the incident energy of UV radiation and th e change in absorbance of BPB/PVB films at 421 and 601 nm using irradi ation wavelengths of 248.5, 298.8 and 366 nm The assessment of the unc ertainties, the effect of the irradiation wavelength and chloral hydra te concentration on the performance of BPB/PVB films and the post-irra diation stability in different storage conditions were investigated. ( C) 1997 Elsevier Science S.A.