Photopolymerization of acrylate suspensions with visible dyes

Polymerization behavior of silica loaded diacrylate suspensions in the presence of color changing dyes was studied via cure depth measurements and photorheology. The dyes have their maximum absorption peak in the visible range; however, spectrophotometry revealed significant absorption also in the UV range where the photoinitiators are active. Thus, the dyes behave as other inert dyes and they affect the curing behavior. The effect of the dye concentration on the sensitivity Dp, critical energy dose Ec and time parameters determined via photorheology was studied and the data was fit to theoretical models. The measured values of 1/Dp, Ec and the photorheology time parameters linearly increase with increasing dye concentration cD as predicted by the models.