3.5. Production of
Force-Degradation Identification by Raman
The Raman spectra of samples after 48 h of heat treatment are presented
in Figure 1a. They exhibited clear differences and were clearly
distinguishable by visual inspection alone. However, the spectra before
24 h of heat treatment appeared similar. In addition, in Figure 4c, the
Raman spectra of samples after different durations of light treatment
appeared similar. Therefore, PCA of the multivariate algorithms was used
to construct the Raman spectral models.