  The chirally symmetric quark-gluon plasma produced in energetic heavy-ion
collisions is predicted to supercool at the late stages of its evolution. The
thermal energy is then transformed into the potential energy associated with an
energetically unfavorable field configuration. Since the system is in an
unstable state it eventually rolls down to the true minimum of the effective
chiral potential. When this motion is described in terms of the sigma-model, we
find that the energy of the coherent $\sigma-$field is very efficiently
converted into pionic excitations due to anharmonic oscillations around this
minimum. The system is expected to partially thermalize before its
disintegration.
