  The problem of the expansion of a relativistic plasma generated when a large
amount of energy is released in a small volume has been considered by many
authors. We use the analytical solution of Bisnovatyi-Kogan and Murzina (1995)
for the spherically symmetric relativistic expansion. The light-curves and the
spectra from transparency of an electron-positron-photon plasma are obtained.
We compare our results with the work of Goodman (1986).
