Hyperspectral Imaging Surface Analysis for Dried and Thermally Modified Wood: An Exploratory Study

Table 2

Band assignment from average spectrum of naturally seasoned and kiln-dried wood.

Peak no. in Figure 4(b)	Wavelength (nm)	Bond vibrations
1	1190–1221	Linked to 2nd overtone of CH-stretching and may correspond to CH3 groups of wood constituents such as lignin assigned to spectra and CH, CH2 groups of cellulose
2	1440	Arises from 1st overtone of C-H stretching and C-H deformation in lignin
3	1447–1491	Linked to 1st overtone of O-H stretching in phenolic lignin, glucomannan, and semicrystalline regions in cellulose, intramolecular H-bond of cellulose
4	1922–1928	Related to O-H asymmetric stretching and O-H deformation of the water molecule; this is expected, as the moisture content was different in the specimens
5	2085–2113	Relates to O-H and C-H stretching and deformations in cellulose and xylan molecules
6	2277	Relates to O-H plus C-C stretching and/or C-H stretching and deformation in cellulose; this peak overlaps the peak at 2236 nm related to lignin via C-H stretching and C-H2 deformations
7	2331	Related to C-H stretching and C-H deformation in hemicellulose and xylan molecules
8	2450–2475	Relates to carbohydrates in general