Photocrosslinkable resins with benzylideneacetophenone (chalcone) structure in the repeat units

Syntheses, characterization and photoreactions of six diglycidyl ethers obtained by condensing 2,2′, 2′,4, and 4,4′-dihydroxychalcones with epichlorohydrin in two different molar proportions have been reported. It has been observed that the well known cyclodimerization and trans-cis isomerization of the chalcone moiety under photoirradiation could be significantly affected to the extent of completely supressing the isomerization in 2,2′, and 2′,4-chalconic resins by steric factors. Increase in molecular weight made the photodimerization difficult in the 2,2′, and 2′,4-chalocnic resins whereas the 4,4′-chalconic resin remained unaffected. It has been suggested that the chalconic resin could be used in photomechanical processes mixed with aryldiazonium fluoroborates. These additives are known to decompose under photoirradiation yielding BF₃ which is a crosslinking agent for the epoxide group.