Table 4: Explanation of IR spectrograph.

Position/cm−1Band origin

3400–OH stretching
2943C–H stretching
1706C=O stretching nonconjugated to the aromatic ring
1610C=O stretching conjugated to the aromatic ring
1520Aromatic ring vibrations
1462Aromatic ring vibrations C–H deformations
1275Aromatic ring vibrations of guaiacyl
1201C–O stretching of syringy
1124Aromatic ester
1027C–H and C–O deformation
820Syringy C–H vibrations