The invention relates to a moisture resistant composition comprising: a) from 20 to 80 weight percent based on the total weight of the composition of a polyetherimide copolymer made from a monomer mixture comprising 3,3′ bisphenol-A dianhydride (BPADA), and 4,4′-diaminodiphenyl sulfone (DDS); b) from 5 to 75 weight percent based on the total weight of the composition of polyetheretherketone (PEEK); and c) from 0 to 30 weight percent based on the total weight of the composition of a filler. The invention relates to a reflector substrate comprising a moisture resistant layer metalized with a reflective layer, wherein the moisture resistant layer comprising the moisture resistant composition. The invention relates to a method for producing a metalized coating without a primer comprising applying a reflective layer directly to a moisture resistant layer in the absence of a primer, wherein the moisture resistant layer comprises the moisture resistant composition.