  The influence of neutrino trapping (NT) on the early cooling evolution of hot
proto quark stars (PQS) with initial temperatures in the range T ~ 40 MeV is
studied. Within a simplified model for the neutrino transport it is shown that
the time for reaching neutrino opacity temperature of T_{opac} ~ 1 MeV is about
10 sec. This is an order of magnitude larger than without NT and of the same
order as the duration long gamma ray bursts.
