Lifetime distribution and non-radiative processes in chromium doped aluminosilicate glass

We present luminescence decay measurements of an aluminosilicate glass doped with chromium for different combinations of excitation and emission wavelengths, obtained between 10-300 K. The luminescence lifetime distribution of the T-4(2) --> (4)A(2) transition has been obtained using the exponential series method and modelled by considering the radiative lifetime distribution in the sample and the effect of non-radiative internal conversion. Good fits to the data have been obtained. The distribution of the radiative luminescence lifetimes shows that there is little correlation between T-4(2) energies and the magnitude of odd parity distortions. The distribution of the energy barrier for non-radiative processes indicates that a significant contribution to barrier crossing comes from tunnelling and that the Cr3+ potential wells must be modelled using confinement potentials rather than simple harmonic approximations.