You can select the particles of the fire, and go to the attribute editor (ctrl+A) then look at the tabs, there should be one of the tabs to the outmost right that have your shader info, find glow under special effects I think it is..

you could also go into Hypershade, select your fire, in hypershade find the option to select shader assigned to selected object. Then Maya will highlight the shader that is assigned to your fire object. Double click it and the Attribute editor will open. there you should be able to find the glow attributes under special effects ..

have fun