  We study the out-of-equilibrium dynamics following a temperature-jump in a
model for a strong liquid, BKS-silica, and compare it with the well known case
of fragile liquids. We calculate the fluctuation-dissipation relation, from
which it is possible to estimate an effective temperature $T_{eff}$ associated
to the slow out-of-equilibrium structural degrees of freedom. We find the
striking and unexplained result that, differently from the fragile liquid
cases, $T_{eff}$ is smaller than the bath temperature.
