  We have studied the nonequilibrium dynamics of spin glasses subjected to bond
perturbation, which was based on the direct change in the spin-spin interaction
$\Delta J$, using photo illumination in addition to temperature change $\Delta
T$. Differences in time-dependent magnetization are observed between that under
$\Delta T+\Delta J$ and $\Delta T$ perturbations with the same $\Delta T$. This
differences shows the contribution of $\Delta J$ to spin-glass dynamics through
the decrease in the overlap length. That is, the overlap length $L_{\Delta
T+\Delta J}$ under $\Delta T+\Delta J$ perturbation is less than $L_{\Delta T}$
under $\Delta T$ perturbation. Furthermore, we observe the crossover between
weakly and strongly perturbed regimes under bond cycling accompanied by
temperature cycling. These effects of bond perturbation strongly indicates the
existence of both chaos and the overlap length.
