PHOTODEGRADATION STUDY OF METHYLENE BLUE (MB) TRAPPED IN POLY (METHYL METHACRYLATE) (PMMA) MATRIX
Abstract
Photochemical reactions of the methylene blue (MB) doped in PMMA matrix was studied
using a UV-visible fibre optics spectrophotometer. The absorbance peak of each MB doped
PMMA sample centered around 660 nm decayed significantly with the increasing of exposure time to UV-visible light. A decrease in absorbance with time indicated that the UV-visible irradiation caused photobleaching of MB in the polymer matrix. The main absorption peaks for each sample increased at higher concentration due to the increase in the number of dye molecules. The absorbance of the sample at lower concentration decreased with time much faster than that at higher concentration of MB. This indicated that a faster photobleaching process occurred at the lower dye concentration of MB compared with that at the higher concentration of MB.
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