PURPOSE: To prepare the titled composition composd of a fluorescent material, a water-soluble binder, a low-melting glass powder and ammonium nitrate, and giving a fluorescent film of a fluorescent lamp having stable luminescence and excellent lamp characteristics even after storing for a long period.
CONSTITUTION: The objective paint can be prepared by mixing (A) a water-soluble binder (e.g. polyethylene oxide) with (B) a low-melting glass powder (e.g. La 2 O 3 .MgO.B 2 O 3 ), (C) a fluorescent material and (D) 0.01W2.0wt%, preferably 0.1W1.0wt%, based on the fluorescent material, of ammonium nitrate. The paint is applied to the inner surface of the glass tube for a ring fluorescent lamp, and dried under the flow of hot air at about 60W70°C to form a fluorescent layer.