The dynamics of electron-spin injection in a heterovalent GaAs/AlGaAs/ZnMnSe structure with a coupled double quantum well (QW) of GaAs/AlGaAs has been studied by means of time-resolved circularly polarized photoluminescence (PL). The circularly polarized PL from the non-magnetic GaAs QW indicates the electron-spin injection from the ZnMnSe/ZnSSe spin generator, when photo-excitation within the ZnSSe barrier is performed by linearly polarized light. The circular polarization develops with an increase in the time delay after the pulsed excitation, which is indicative of the spin-injection dynamics. We find that the rise-time of the circular polarization, ranging from 0.05 to 0.5 ns, as well as the maximum value of the polarization degree depends strongly on the power density of excitation light in the ZnSSe. (c) 2013 Elsevier B.V. All rights reserved.