ZnSe single crystals, obtained by the Solid Phase Recrystallization (SPR) method under three different pressure conditions, 10 and 5 atm of Se, and 2 atm of argon, have been investigated by means of photoluminescence (PL) and optical microscopy. Special attention has been paid to the surface state of the samples. Samples recrystallized under 10 atm of Se present the best rate between the PL response for the excitonic zone and the deep level one that shows a “clean” PL emission without significant peaks and/or bands. The presence of slip bands has been detected and analysed by means of optical microscopy and photoluminescence. In order to study the changes introduced by post growth thermal treatments, we have analysed the low temperature PL response on SPR samples after different thermal treatments. Striking changes have been detected in the PL response before and after the thermal treatment. The involved mechanisms have been studied.