A method of making a polyetherimide includes melt mixing a composition comprising an aromatic bis(ether anhydride) and a diamine to form a polyetherimide wherein melt mixing occurs at a temperature 50 to 225° C. greater than the glass transition temperature of the polyetherimide and after the composition attains a weight average molecular weight that is greater than or equal to 20% of the weight average molecular weight of the polyetherimide melt mixing occurs at a pressure less than atmospheric pressure.