Monitoring polymer curing progress through optical attenuation coefficient variations

Abstract

The curing process of polymers has a crucial influence on their final properties. In this work, the optical attenuation coefficient (OAC) of the polymer was developed to reveal the polymerization reaction and proposed a non-contacted cure monitoring method to estimate the curing degree based on the OAC measurement. The method involves acquiring the interference spectra of the polymer specimen using optical coherence tomography (OCT) and extracting the time-varied OAC from the amplitude-frequency of the spectra. Since polymer curing is accompanied by an increase in refractive index, the gradual convergence in the refractive index of the matrix and fillers leads to a decrease in the OAC. For validation, the reliability, repeatability, and stability experiments of this method were implemented successively on a dental polymer resin and verified its feasibility in monitoring the curing process. Then, the quantitative measuring performance under different curing conditions was further verified on another polymer composite. Finally, three commercial dental composite materials were successfully measured for the curing degree and confirmed the practicability of the OAC-OCT-based method in monitoring cure application.