The green SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor is a well-known persistent material for a wide region of applications such as lighting, traffic signs, interior decoration and medical application. Double activated SrAl₂O₄:Eu²⁺, Dy³⁺ with improved properties has been synthesized through solid state route at different firing atmospheres (reduction, vacuum, oxygen and CO₂ wet gas) and heating times (1 h to 8 h). At the beginning the powders were heat treated for 2 h with a heating rate of 10C/min. The phosphor prepared at different firing atmospheres and heating times exhibited a different wavelength and intensity of PL spectra. The emission intensity becomes stronger as the heating times increases from 1 h to 4 h. The difference found from these spectra maxima is rationalized based on the presence of intermediate phases and also on the diffusion activities of activator and co-activator in the host matrices.