insulation and non condensation advantages associated with wood core window frame while eliminating the disadvantages associated with mildew rot cracking and flammability application_number US 91866904 A description the window frame assembly of the present invention is shown generally as 10 in fig1 the window frame assembly 10 is incorporated into a semi circular fixed panel window 12 the window frame assembly 10 may of course be incorporated into any desired window of any desired radius or configuration including but not limited to circular windows oval windows and windows with undulating curved perimeters the window includes the curved window frame assembly 10 and a straight sill assembly 14 which define an area containing insulating glass contained by the window frame assembly 10 and sill assembly 14 muntin bars 18 are releasably mounted in a sunburst pattern on the interior of the window 10 as shown in fig2 the exterior side of the window 12 is to the left and the interior is to the right the window glass 16 includes two panes 20 and 22 defining an interposed airspace 24 and separated by spacers 26 the window glass 16 is held in position on the interior frame by a pultruded interior glazing stop 28 screwed into or otherwise secured to the curved frame assembly 10 and a pultruded interior sill glazing stop 30 screwed into or otherwise secured.