We have investigated exciton luminescence spectra, decay behaviors, and their temperature dependence in single-walled carbon nanotubes in micelles. The temperature dependence of luminescence spectra can be explained by the one-phonon process associated with the radial breathing mode in the single-walled carbon nanotube. The luminescence decay behavior suggests that the signal is composed of various exponential decays with different decay times. These experimental results are explained by the existence of trapping centers on the nanotube. (c) 2004 Elsevier B.V. All rights reserved.