Research About the Variation of Blue Ballpoint Writting Inks Exposured to Ultraviolet Light by Time
Wang Jian, Sun Suqin, Luo Guoan, Zhang (Department of Chemistry, Tsinghua University, Beijing 100084) Wang Yanji (Department of Forensic Science and Technology, Criminal Police College of China,Shenyang 110035) Feng Jimin (Institute of Forensic Scienc
The Fourier transform-infrared spectra of the blue ballpoint inks exposed to ultraviolet light were studied. This research discovered that the solvents volatilized rapidest, and then the rate of polymerization and cross-link process of the epoxy resin took second place, and the decomposition of triarylmethane dyes was slower, and alkyd resin was relatively steady. It was as a new means for further distingusihing writting inks. Meanwhile, the means could determine the age of inks. The relative ratio of peak height was applied to describe the process of the change and on the basis of the curve fitting the errors coming from different strokes could be aviod. The advantages above are very important in practical examinations.