Disclosed herein is a composition comprising a poly(arylene sulfide); a polysiloxane/polyimide block copolymer; glass fiber and an optional platy filler. The polysiloxane/polyimide block copolymer has greater than or equal to 10 weight percent siloxane content, based on the total weight of the polysiloxane/polyimide block copolymer. The composition retains greater than or equal to 60% of the initial viscosity after being retained at 320° C. for 30 minutes and the composition has an OSU peak heat release less than 45 kW/m2 when measured using the method of FAR F25.4 and according to FAR 25.853 (d). Articles comprising the composition are also described.