  We report experimental evidence that a polymer stretched at constant strain
rate $\dot\lambda$ presents complex memory effects after that $\dot\lambda$ is
set to zero at a specific strain $\lambda_w$ for a duration $t_w$, ranging from
$100$s to $ 2.2\times10^5$s. When the strain rate is resumed, both the stress
and the dielectric constant relax to the unperturbed state non monotonically.
The relaxations depend on the observable, on $\lambda_w$ and on $t_w$.
Relaxation master curves are obtained by scaling the relaxation time as $t/\ln
(t_w)$. The dielectric evolution also captures the distribution of the
relaxation times, so the results impose strong constraints on the relaxation
models of polymers under stress and they can be useful for a better
understanding of memory effects in other disorder materials.
