[ 0023 ] fig1 shows a cross - sectional view of one embodiment of a sash of the present invention . an insulated sash frame 100 , made of a weather and moisture resistant material such as , for example , metals , such as steel and aluminum , and plastics such as pvc , polypropylene , plastic composites , and the like , is formed into a perimeter around a geometrical form of the window pane to be formed . in one embodiment , the sash perimeter is rectangular , but the form may be square , circular , elliptical , or irregular in shape as the final window requires . in each of these cases , however , the same cross section of the insulated sash frame 100 may advantageously be used . the insulated sash frame 100 includes two viewing sides , represented in fig1 as a first viewing side 110 and a second viewing side 120 . the first viewing side 110 and the second viewing side 120 form substantially parallel viewing surfaces based on the major geometrical region formed by the perimeter of the insulated sash frame 100 . the insulated sash frame 100 also includes a plurality of bonding recesses 130 . the bonding recesses 130 include a first bonding recesses 130 a associated with the first viewing surface 110 , and a second bonding recess 130 b associated with the second viewing surface 120 . both of the bonding recesses 130 are oriented to have a bonding surface 132 directed towards the second viewing surface 120 . in the embodiment of fig1 the two bonding surfaces 132 a and 132 b are on the first bonding recess 130 a and second bonding recess 130 b respectively , and each of the bonding surfaces 132 a and 132 b are oriented towards the second viewing surface 120 . as described in detail below , each bonding recess 130 is located at a distance above the base of the insulated sash frame 100 which is directly proportional to its distance from the second viewing surface . at least one bonding material 140 , such as the various sealant materials used commercially for such purposes , including silicone adhesives , hot melt butyl material , modified polyurethane sealants , and the like , are applied to each bonding surface 132 of each bonding recess 130 . preferably , the bonding material 140 is applied to each of the bonding surfaces 132 . a pane 150 , which can be glass , plastic , or another clear viewing material , is also applied to the bonding recesses 130 , after application of the bonding material 140 , in order from the first viewing side 110 to the second viewing side 120 . thus , a first bonding material 140 a can be applied to the first bonding surface 132 a of the first bonding recess 130 a , upon which a first glass pane 150 a is mounted , followed by application of a second bonding material 140 b to a second bonding surface 132 b of a second bonding recess 130 b , upon which a second glass pane 150 b is mounted . these bonding materials can be applied by automated equipment at a first station along the assembly line , which preferably rapidly applies a continuous bead of the bonding material about the entire periphery of the respective binding recess 130 and the sash frame . alternatively , bonding materials 140 a and 140 b are applied in tandem to the first bonding surfaces 132 a and 132 b of the first bonding recess 130 a and second bonding recess 130 b at the first viewing surface 110 and second viewing surface 120 , respectively . then a first glass pane 150 a and second glass pane 150 b are mounted on the first bonding recess 130 a and second bonding recess 130 b by way of the first bonding material 140 a and second bonding material 140 b , respectively . in an automated commercial process this glass mounting step can be rapidly carried out at a second station along the assembly line . once the pane 150 b has been mounted , a glazing bead 160 is applied to the sash 100 , from the direction of the second viewing surface and abutting the second viewing surface 120 and the second pane 150 b to provide a finished , even look to the sash , hide the junction of the bonding recess 130 b and the glass pane 150 b , and protect the bonding material 140 b between the bonding surface 132 b of the bonding recess 130 b and the glass pane 150 b from the environment . in this manner , the steps of glazing the sash 100 can be accomplished either simultaneously or serially , so long as the actual mounting of panes is performed starting from the first viewing surface and moving towards the second viewing surface . for example , each step may be performed simultaneously for all bonding recesses 130 before moving to the next step , whereas in serial each step may be performed for each bonding recess 130 a before moving to the next bonding recess 130 b . once the glass panes are set , the resulting sash 100 includes a central insulating region 170 which provides thermal insulation between the first viewing surface 110 and second viewing surface 120 of the window sash 100 . [ 0032 ] fig2 shows a cross - sectional view of one embodiment of a sash of the present invention , including relative dimensional callouts that are not necessarily to scale . each bonding recess 130 has an associated bonding recess maximum elevation , 135 a and 135 b , as measured from the base of the sash frame 100 , the bonding recess maximum elevation defined as , for example , the distance between the base of the insulated sash frame 100 and the top of the bonding recess 130 . for each bonding surface 132 , the bonding surface 132 also has a bonding recess minimum elevation 145 defined as , for example , the distance between the base of the insulated sash frame 100 and the base of the bonding surface 132 . as can thus be seen , the height of the bonding recess 130 itself is the difference between the bonding recess maximum elevation and the bonding recess minimum elevation . the central insulating region 170 has an insulating region height 175 defined as , for example , the distance between the base of the insulated sash frame 100 and the bottom of the region constituting the central insulating region 170 . similarly , the glazing bead 160 has a glazing bead elevation 165 defined as , for example , the distance between the base of the insulated sash frame 100 and the top of the glazing bead 160 . while for aesthetic purposes this glazing bead elevation 165 may be the same as the bonding recess maximum elevation 135 a on the opposite viewing side , this does not necessarily have to be the case , and these two elevations can have different elevations . based on these values , and the selected geometry of the sash , the preferred relative dimensions of each bonding recess , bonding surface , and glazing bead can be readily determined . for example , if a first viewing surface 110 has a bonding recess 130 a with a bonding recess maximum elevation 135 a of 4 inches , and a bonding recess minimum elevation of 3 inches , then the height of the bonding recess itself would be 1 inch . as for the bonding recess maximum elevation 135 b for second viewing surface 120 , this distance will be defined , for example , by : as used above , ε represents a margin of error added to equation 1 wherein 0 ≦ ε ≦ about 1 inch , for example , to ensure that panes nearer to the first viewing surface can easily be mounted from the second viewing surface . thus , while it is possible that the elevation 135 b can be equal to that of 145 a , it is most preferable that the bonding recess maximum elevation 135 b be less than the bonding recess minimum elevation 145 a , again for the purposes discussed above . when intermediary viewing surfaces between the first viewing surface 110 and second viewing surface 120 are included in the sash frame ( to create , for example , triple glazed windows ), then the formula of equation one is simply applied to each viewing surface recursively , beginning with the first viewing surface . in each such case , however , it is essential for the purposes of the present invention that all of the bonding recesses 130 face in the same direction , and in the case of fig1 towards the second viewing surface 120 . other equations for determination can similarly be developed based on different measures of spacing and as required by varying window design and sash material . [ 0036 ] fig3 a and 3b show a cross - sectional view and perspective view , respectively , of one embodiment of a hollow sash of the present invention , again including integral spacer frames therein . as described above , a hollow sash 100 has a first viewing surface 110 and a second viewing surface 120 , whereupon a first bonding recess 130 a and second bonding recess 130 b are placed respectively . bonding materials 140 a and 140 b are coupled to glass panes 150 a and 150 b at the bonding surfaces 132 a and 132 b of the bonding recesses 130 a and 130 b , respectively . a glazing bead 160 is applied at the second viewing surface 120 against the bonding recess 130 b and glass pane 150 b . the glazing bead is coupled to the sash frame 100 , for example , by means of a glazing bead lock 230 , which serves to latch the glazing bead 160 to the sash frame 100 . referring next to fig4 a and 4b , a triple - glazed window is shown which employs a third bonding recess which is added to the region of the sash 100 within the central insulting region 170 , and once again with this third bonding recess facing in the same direction as the first and second bonding recesses . in particular , in the case of fig4 a and 4b , a hollow sash 100 has a first viewing surface 110 and a second viewing surface 120 . in this case , a first bonding recess 130 a is located at the first viewing surface 110 and faces the second viewing surface 120 . a second bonding recess 130 b is located at the second viewing surface 120 and also faces that second viewing surface 120 . a third bonding recess 130 c is located between the first and second bonding recesses , 130 a and 130 b , respectively , and once again faces the second viewing surface 120 . bonding materials 140 a , 140 b and 140 c are coupled to glass panes 150 a , 150 b and 150 c , respectively , at the bonding surfaces 132 a , 132 b and 132 c of respective bonding recesses 130 a , 130 b and 130 c . a glazing bead 160 is once again applied at the second viewing surface 120 against the bonding recess 130 b and glass pane 150 b . the glazing bead is once gain coupled to the sash frame 100 , for example , by means of a glazing bead lock 230 , which serves to latch the glazing bead 160 to the sash frame 100 . additional bonding recesses could also be added to the region of the sash 100 within the actual insulating region 170 , once gain so long as each of these additional bonding recesses faces the same direction as the first , second and third bonding recesses . the central insulating region 170 may include desiccant material ( not shown ) to absorb moisture accumulated in the insulated region 170 . although the invention herein has been described with reference to particular embodiments , it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention . it is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims .