The performance of 7‐hydroxycoumarin‐3‐carbonitrile and 7‐hydroxycoumarin‐3‐carboxylic acid as fluorescent probes for monitoring of cationic photopolymerization processes by FPT

Abstract The applicability of 7‐hydroxycoumarin‐3‐carbonitrile (1) and 7‐hydroxycoumarin‐3‐carboxylic acid (2) as fluorescent probes for monitoring of cationic photopolymerization processes by fluorescence probe technique (FPT) was evaluated in comparison to the response of 7‐diethylamino‐4‐methylcoumarin (C1). Triethylene glycol divinyl ether and diphenyliodonium hexafluorophosphate were used as an example monomer and a cationic photoinitiator, respectively. It has been found that the probe 1 withstands the cationic polymerization conditions and provides correct probe response. The probes 2 and C1 undergo side reactions under the cationic polymerization conditions that make them unusable for monitoring of the polymerization progress at high monomer conversions. The application of 1 as an amine‐free probe for monitoring of curing progress of photocurable coatings cured by cationic photopolymerization is proposed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013