A spectrocolorimetric study on the effect of ultraviolet irradiation of four tropical hardwoods

• Published in: Bioresource technology 2004-05, Vol.93 (1), p.37-42
• Main Authors: Pastore, Tereza C.M., Santos, Kelly O., Rubim, Joel C.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Brazil; CIE- [formula omitted] parameters; Color; Colorimetry; Forestry; Fundamental and applied biological sciences. Psychology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Kubelka-Munk; Lignin - metabolism; Plants - radiation effects; Quality of wood and forest products; Spectrum Analysis; Tropical hardwood; Ultraviolet Rays; UV irradiation effect; Wood; Wood surface
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2003.10.035

Colour modifications caused by exposure to artificial UV radiation (350 nm, UV-A) of four tropical hardwoods, jatobá, angelim vermelho, garapeira, and marupá, have been evaluated by diffuse reflectance spectroscopy and by the CIE- L ∗a ∗b ∗ system. To obtain the absorption maxima of the chromophore species formed during UV irradiation, Kubelka-Munk (K-M) difference spectra (non-irradiated–irradiated) have been recorded as a function of exposure time. The K-M difference spectra have shown that the investigated species develop strong absorption bands in the visible region upon UV irradiation that were assigned to the formation of lignin and extractive photodegradation products. The K-M difference spectra and CIE- L ∗a ∗b ∗ parameters (Δ L, Δ a, and Δ b) have shown that marupá is the wood species that suffers the major changes upon UV irradiation while angelim vermelho was the least affected.