Study on Fluorescence Intensity Determination of Rare Earth Europium Complexes UV-Photochromic Inks

The paper discussed the preparation of rare earth europium complexes ultraviolet rays (UV) photochromic ink and the influences of factors, such as europium complexes using a rare earth ternary complex of Eu ion with 3-benzoylbenzoic acid and phenathrolinephen [Eu(BA)3Phen] content upon printing ink formula. In the experiment, we utilized fluorescence spectrophotometer to make quantitative determinations of the relative fluorescence intensity of rare earth europium complexes and different proportions of UV photochromic ink samples. Besides, we made further analysis and studied their relative fluorescence intensity and fluorescence spectrum. Printing ink samples were made in the offset printability tester with the pressure of 200N, 500N, or 800N.The results showed that: printing pressure had a little influence on the fluorescence intensity of samples, for instance, with the 500N pressure, the relative fluorescence intensity could be easily tested; with rare earth europium complexes proportion increasing, the relative fluorescence intensity became enhanced. In this paper, we studied the relative fluorescence intensity for different proportions of photochromic ink. It demonstrated that through the quantitative determination of the relative fluorescence intensity of samples, the best content ranges for adding rare earth europium complexes was between 8.5% and 9.5%. From the fluorescence spectrum, we got conclusion that photochromic ink reached the crest of 616.8nm.