中文摘要：

暴露于室外环境的木材或木制品,由于受气候因子的作用其表面性状和品质发生劣化,主要表现为木材变色,大大降低其利用价值。以人工林杉木为研究对象,利用模拟太阳辐射的氙光衰减仪对木材表面进行光劣化处理,采用傅里叶变换红外（FTIR）光谱技术分析了木材光变色过程中化学成分的变化,建立了木材变色与化学成分变化之间的关系。试验结果表明：光照过程中,1512,1462,1269和1227cm^-1处与木质素有关的吸收峰强度明显降低,1720～1735cm^-1处非共轭羰基伸缩振动吸收明显增强,木材表面发生光氧化反应,木质素明显降解,同时不断有新的羰基化合物生成;光照80h内,木质素的降解以及羰基化合物的生成速度较快,此后变化不显著;木材表面部分多糖物质（纤维素和半纤维素）被氧化降解。研究表明,木材光照过程中的颜色变化（ΔE＊）与木质素的降解以及羰基官能团的生成密切相关。

英文摘要：

Wood or wood products undergo rapid degradation of surface characteristics and quality indicated by changes in wood color during outdoor exposure owing to a combination of various weathering factors, which may result in significant reduction in utilization values of wood. In the present study, photodegradation of wood surfaces of Chinese fir （Cunninghamia lanceolata） was carried out by a Xenon test chamber which can simulate sunlight irradiation. A Fourier transform infrared （FTIR）spectroscopy technique was used to study chemical changes caused by irradiation during photo-discoloration of wood surfaces, and the relationship between the changes in color and chemical composition was established. Results indicated that, during the process of irradiation, the intensity of absorption bands at 1 512, 1 462, 1 269 and 1 227 cm^- 1 decreased significantly, accompanied by a successive increase in the intensity of band at 1 720-1 735 cm^-1. Lignin was the most sensitive component to the degradation process and underwent severe photodegradation during the process of irradiation. This was accompanied by formation of new carbonyl compounds, which indicated the photo-oxidation of wood surfaces. In the initial 80 h of irradiation, the degradation of lignin and formation of carbonyl groups were intense, and then became insignificant in longer exposure duration. Degradation of polysaccharides （cellulose and hemiceUulose）also occurred during the process. Overall, color changes （△E^＊ ）were correlated well with the degradation of lignin and relative increase in the content of carbonyl groups during the process of irradiation.