Changes in the Properties of Light-Irradiated Wood with Heat Treatment. Part 1. Effect of Treatment Conditions on the Change in Color

Abstract

Summary The effect of heat treatment on changing the color of light-irradiated wood was investigated. The change in the lightness, ∆L*, of light-irradiated wood with heat treatment was much greater than that of unirradiated wood. The chroma coordinates, ∆a*, of irradiated wood increased with treatment temperature and time. ∆b* decreased after showing a sharp increase with a short period of heat treatment. It is thought that the changes are related to a change in the chemical composition which was accelerated by heat. With low temperature treatment, the color of irradiated wood changed remarkably with high relative humidity. Little change in color was observed with low relative humidity. Therefore, heat and the presence of water accelerated the change in the color of irradiated wood. This treatment is available as a new coloring method.