[en] For around ten years, intense attention has been devoted to materials which exhibit strong persistent luminescence. The Eu²⁺ doped SrAl₂O₄ is probably the best one. Co-doping with other trivalent rare earth ions, especially with Dy³⁺, enhances the persistent luminescence. Co-doping with Sm³⁺ leads to a drastic decrease in the efficiency of persistent luminescence, however. In this paper, the results of a careful analysis of the dynamic luminescence properties of SrAl₂O₄:Eu²⁺ and co-doped either with Dy³⁺ or Sm³⁺ under different excitation schemes are presented. The temporal transients and time resolved luminescence spectra were analysed with pulsed UV excitation at 355 nm provided by the third harmonic of a Nd:YAG laser. Then continuous wave excitation at 360 nm was also applied simultaneously with the pulsed UV excitation. The profile of the transient luminescence was found to be strongly dependent on the excitation scheme, especially on the pumping power at 355 nm. In addition to the Eu²⁺ decay, other population processes were found to occur. Two components were observed for all the materials studied. In order to carry out a complete analysis of the data, the positions of the 4f and 5d energy levels for the R³⁺ and R²⁺ ions in the energy gap of SrAl₂O₄ were determined