This invention relates to methods for forming a polymer, including continuously depositing a polymer extrudate that is above its glass transition temperature onto a lower molding surface of a first mold in a manner that reduces shear stress in the polymer extrudate, heating the lower molding surface to maintain the polymer extrudate above the glass transition temperature, applying an upper molding surface of a second mold to at least the exposed upper surface of the polymer, allowing the polymer to transition to below the glass transition temperature while within or between the upper and lower molding surfaces, and providing heat sinks spaced relative to each other through the pressure forming zone, wherein a heat sink more advanced through the pressure forming zone is controlled to a lower temperature to progressively reduce the temperature of the polymer as it advances through the pressure forming zone.