  Phase separation may be driven by the minimization of a suitable free energy
${\cal F}$. This is the case, e.g., for diblock copolimer melts, where ${\cal
F}$ is minimized by a steady periodic pattern whose wavelength $\lambda_{GS}$
depends on the segregation strength $\alpha^{-1}$ and it is know since long
time that in one spatial dimension $\lambda_{GS} \simeq \alpha^{-1/3}$. Here we
study in details the dynamics of the system in 1D for different initial
conditions and by varying $\alpha$ by five orders of magnitude. We find that,
depending on the initial state, the final configuration may have a wavelength
$\lambda_{D}$ with $\lambda_{min}(\alpha)<\lambda_{D}<\lambda_{max}(\alpha)$,
where $\lambda_{min} \approx \ln (1/\alpha)$ and $\lambda_{max}\approx
\alpha^{-1/2}$. In particular, if the initial state is homogeneous, the system
exhibits a logarithmic coarsening process which arrests whenever
$\lambda_{D}\approx\lambda_{min}$.
