  Using molecular dynamics computer simulations we investigate how in silica
the glass transition and the properties of the resulting glass depend on the
cooling rate with which the sample is cooled. By coupling the system to a heat
bath with temperature $T_b(t)$, we cool the system linearly in time,
$T(t)=T_i-\gamma t$, where $\gamma$ is the cooling rate. We find that the glass
transition temperature $T_g$ is in accordance with a logarithmic dependence on
the cooling rate. In qualitative accordance with experiments, the density shows
a local maximum, which becomes more pronounced with decreasing cooling rate.
The enthalpy, density and the thermal expansion coefficient for the glass at
zero temperature decrease with decreasing $\gamma$. We show that also
microscopic quantities, such as the radial distribution function, the bond-bond
angle distribution function, the coordination numbers and the distribution
function for the size of the rings depend significantly on $\gamma$. We
demonstrate that the cooling rate dependence of these microscopic quantities is
significantly more pronounced than the one of macroscopic properties.
Furthermore we show that these microscopic quantities, as determined from our
simulation, are in good agreement with the ones measured in real experiments,
thus demonstrating that the used potential is a good model for silica glass.
The vibrational spectrum of the system also shows a significant dependence on
the cooling rate and is in qualitative accordance with the one found in
experiments. Finally we investigate the properties of the system at finite
temperatures in order to understand the microscopic mechanism for the density
anomaly. We show that the anomaly is related to a densification and subsequent
opening of the tetrahedral network when the temperature is decreased, whereas
