A method for making window with a decorative polymer panel assembly. The method can include forming a polymer grille by cutting a design into a polymer with a low-moisture content. The polymer grille can have a frame portion and a design portion. A seal can be contiguously disposed about a perimeter of the frame portion. A grille assembly can be formed by disposing a translucent panel on each side of the seal, forming an air space with the polymer grille disposed within the air space. The grille assembly can be pressed, heated and cooled, forming the decorative polymer panel assembly. The decorative polymer panel assembly can be disposed within a frame which can be disposed within an opening of a structure.