A New Trial for Measurement of Degree of Photo-curing of Photo-reactive Resins.

A facile measuring apparatus for studying filter effect on UV curing reaction of acrylate monomers was prepared. Correlation of depth of curing of the monomer and conversion of C= C double bond was examined with this apparatus. The conversion of C=C of the monomer decreased from 75.0% to 19.5%with increasing depth of curing of 2-ethyl-2-hydroxymethy1-1, 3-propanediol triacrylate (TMPTA) under UV irradiation with 40 mJ/cm2 owing to filter effect of acrylate monomer and photoinitiator. The depth of curing of the monomer increased with an decrease in the concentration of photoinitiator in monomer. The depth of curing showed the largest value by use of TMPTA for monomer and 2-methyl1-[4- (methylthio)pheny1]-2-morpholino-1-propanone for photoinitiator.