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The Scientific World Journal
Volume 2014, Article ID 102524, 8 pages
Research Article

Modeling and Assessment of Long Afterglow Decay Curves

1Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 11031, Taiwan
2Department of Dentistry, Taipei Medical University Hospital, Taipei 11031, Taiwan
3Department of Civil Engineering, Feng Chia University, Taichung 407, Taiwan
4Department of Pediatrics, Taichung Veterans General Hospital, Taichung 407, Taiwan

Received 23 January 2014; Accepted 17 August 2014; Published 14 September 2014

Academic Editor: Roberto Rivelino

Copyright © 2014 Chi-Yang Tsai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Multiple exponential equations have been successfully fitted to experimental long afterglow decay curve data for some phosphor materials by previous researchers. The calculated decay constants in such equations are used to assess the phosphorescence characteristics of an object. This study generates decay constants from experimental test data and from existing literature for comparison. It shows that the decay constants of an object may not be invariant and that they are dependent on phosphor material, temperature, irradiation intensity, sample thickness, and phosphor density for samples. In addition, the use of different numbers of exponential components in interpretation leads to different numerical results for decay constants. The relationship between the calculated decay constants and the afterglow characteristics of an object is studied and discussed in this paper. The appearance of the luminescence intensity is less correlated to the decay constants than to the time-invariant constants in an equation.