| Abstract: | Several intramolecular charge transfer fluorescence probes, such as the dansyl amides (1a-d), 4-dimethylamino-4′-nitrobiphenyl (2) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (3), have been developed and evaluated. The fluorescence emission of the probes is sensitive to both the solvent polarity and medium microviscosity. A spectral blue shift, attributed to an increase in microviscosity, was observed as polymerization proceeded. Therefore, these fluorescence probes can be used for monitoring polymerization processes. The correlation between the fluorescence emission intensity ratio and degree of cure is linear in various formulations, which may be cured either photochemically or thermally. The selectivity and sensitivity of the fluorescence probes have been investigated. 4-Dimethylamino-4′-nitrobiphenyl (2) was found to be the most sensitive probe to both solvent polarity and medium microviscosity. © 1996 John Wiley & Sons, Inc. |
