The resonances corresponding to the two double bond carbons appear between 129 and 130 ppm in the C spectrum (Figure ) and therefore are also representative of the HA monomer concentration. These peaks exhibited area shrinkage, broadening, and up-field shift concomitant with the light exposure time, similar to those previously analyzed in the 1 H spectra. Integration of the peak areas yielded a conversion profile that closely resembles that of the 1 H-spectrum (Figure ). Repeating this experiment several times, we found that the C-spectrum consistently shows a slightly higher conversion than the 1 H-spectrum by about 4%. We interpret this to be caused by the significantly longer relaxation time required for the collection of the C-spectrum (d1 = 60 seconds) to capture the signal, in contrast to the 1 H-spectrum (d1 = 10 seconds). As a result, C-scans producing adequate S/N took about 13 minutes during which the polymerization could potentially continue to react slightly despite the light source being shut off. This effect may be mitigated by including relaxation agents within the resin to reduce the required collection time of C-spectra and thus collect each data point more rapidly. To investigate whether the polymerization kinetics, as measured by NMR, agree with established photopolymerization theory, we repeated the measurements as a function of light intensity.