Ultraviolet radiation is a very useful electromagnetic wave
commonly applied in germicidal and chemical curing processes of
many products such as foods, medicines, polymers and printing
materials. In these applications, UV exposure dose is important for
effectiveness and it should be regularly monitored and controlled.
Currently, available techniques used in UV dose determination
include photoelectric measurement [1] and colorimetric methods.
The colorimetric method offers an attractive intrinsic feature in the
development of equipment-free direct visual detection or indicators.
Classes of dyes commonly used in colorimetric sensor for
UV doses are spiropyran or spirooxazine. This type of photochromic
dyes change from colorless to darker color upon exposure to UV
radiation that is not easily judged for the critical UV dose [2,3].
Furthermore, the desirable tunable sensitivity of colorimetric
sensing materials has not been well assessed for such compounds.