The lifetime of a disoriented chiral condensate formed within a heat b
ath of pions is calculated assuming temperatures and densities attaina
ble at present and future heavy-ion colliders. A generalization of the
reduction formula to include coherent states allows us to derive a fo
rmula for the decay rate. We predict the half-life to be between 4 and
7 fm/c, depending on the assumed pion density. We also calculate the
lifetime in the presence of higher resonances and baryons, which short
ens the lifetime by at most 20%. [S0031-9007(98)07558-9].