Influence of Different Wave-lengths Artificial Light on Surface Discoloration of Dyed Veneer

Dyed Wood is rapidly degraded by short-wavelength UV radiation, and its degree of discoloration correlate well with the wave length. In the paper we test this hypothesis and analyze chemical change of dyed wood surface affected by UV radiation. So that it will be beneficial for further study on synthesis of photo stabilizer. In this research, dyed veneers are irradiated by artificial light using an ultraviolet accelerated weathering device including 5 different wavelengths (UV to visible). CIE (1976) L*a*b* color measuring system is applied to describe the photo-induced discoloration process of dyed veneer. The reflection curves of spectrum and K-M difference spectra show the diverse change of light absorption and reflection. The results reveal that, samples color is great influenced by 313nm and 340nm UV light, the color stability of dye stuffs is rapidly decreased while stimulated by 254nm UV light. The fastness of dyed veneer has a positive relationship with dye stuffs, Acid Red GR dyed veneer just suffer slight yellowing due to the stability of dye, while Acid Blue V dyed veneer fade obviously and get a tendency of reddish.