Application of Aminocoumarins for the Role Offluorescent Molecular Probe of Cationic Photopolymerization Process

Coumarin (benzo-α-pyrone) derivatives are wide and very important group of chemical compounds. Today, they are used in many areas of industry and science. Due to their low toxicity, there is the possibility of use coumarins in biology, medicine, perfumery and cosmetics industry. Coumarin derivatives have interesting ability to emit fluorescence in the visible range upon excitation of the molecule to a higher energy level after exposure of UV radiation. Coumarin substitution of certain functional groups (including the amino group) can affect the fluorescence shift to shorter or longer wavelengths.In this research an attempt has been made to demonstrate the use of the technique of molecular fluorescence probe FPT (Fluorescence Probe Technology) to monitor the cationic photopolymerization process of the triethylene glycol divinyl ether (TEGDVE), using for that purpose ten commercially available coumarin derivatives: Coumarin 1, Coumarin 120, Coumarin 102, Coumarin 153 and Coumarin 6H. Spectroscopic characteristics of all chemical compounds were investigated, which included measurements of absorbance and fluorescence characteristics. Then, in the spectroscopy studies, the changes of the probe fluorescence were collected, monitoring the physicochemical changes occuring in the composition, ie. changes of both microviscosity and polarity of enviroment in which the coumarin probe was located. The utility of the aminocoumarins for the monitoring of progress of photopolymerization reactions was tested using fluorescence intensity ratio R, the probe sensitivity S and the number of progress of the reaction β. Obtained results revealed that the majority of the compounds tested can be successfully qualified for the role of molecular fluorescent probes capable of monitoring the cationic photopolymerization. It has been found that the presence of amino groups in the basic structure of the coumarin derivative is not a factor limiting the usefulness of these compounds as molecular probes of FPT method. Acknowledgment Research financed within the project LIDER(LIDER/014/471/L-4/12/NCBR/2013) by The National Centre for Research andDevelopment (NCBiR)