Patents
The invention provides a process for the preparation of a long decay luminescent powder having the basic composition comprising an alkaline earth aluminate, an activator such as Eu and a co-activator has been disclosed. The said Luminescent powder has been synthesized by use of an alkaline earth metal salt along with single phase alumina, an activator and a co-activator. The after glow was found to be more than 150 hours. The process uses a reducing agent in the form of carbon or an organic compound, mixed in the starting material mixture that provides a reducing atmosphere in situ within the mass upon heating.