The effect of three electron donors on the initiator system efficiency of photopolymer film photosensitized by methylene blue

Photopolymer film has been widely used in optical devices. However, the low initiator efficiency limits its wider development. In this study, Methylene blue (MB)/N-methyldiethanolamine (MDEA) and MB/1,4-diazabicyclo [2.2.2]octane (DABCO) were first adopted as initiator system in photopolymer film and compared their initiator system efficiencies with the common initiator system MB/triethanolamine (TEA) by a self-established single-beam exposure setup. The MB/MDEA showed the highest performance, while the MB/DABCO was the poorest. The quantum yield, bleaching rate and saturated exposure of the MB/MDEA were 3.31 times, 2.62 times and 2.49 times, respectively, higher than those of the MB/TEA. This order of initiator system efficiencies (MB/MDEA > MB/TEA > MB/DABCO) is exactly consistent with the order of proton transfer efficiencies of the electron donors (MDEA > TEA > DABCO). Furthermore, high proton transfer efficiency and excellent migration of electron donors are helpful to improve initiator system efficiency via surface micromorphology analysis.