Patent Publication Number: US-2009233020-A1

Title: Glazing assembly and method

Description:
PRIORITY CLAIM 
     The present application claims priority to U.S. provisional application Ser. No. 60/973,823, entitled GLAZING ASSEMBLY AND METHOD, which was filed on Sep. 20, 2007 and is hereby incorporated herein, by reference, in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention pertains to glazing assemblies, and the like, and more particularly to these assemblies that include at least two substrates, which are spaced apart from one another on either side of an airspace, and a functional coating, borne by at least one of the substrates, within the airspace. 
     BACKGROUND 
     Insulating glass (IG) units are glazing assemblies that typically include at least a pair of panels, or substrates, joined together such that a major surface of one of the substrates faces a major surface of the other of the substrates, and an airspace is enclosed between the two substrates. At least one of the substrates is transparent, or light transmitting, and may bear a functional coating, for example, a low emissivity coating or a photovoltaic coating, on the major surface that faces the major surface of the other substrate. Those skilled in the art appreciate that the design of this type of assembly should prevent the ingress of excess moisture into the airspace, thereby protecting the integrity of the functional coating. Although various designs have been proposed to address this need, there is still a need for new and improved IG unit-type glazing assembly designs, as well as related, cost-effective, methods of manufacture. 
     BRIEF SUMMARY 
     Glazing assemblies, according to embodiments of the present invention, include a functional coating, for example, a photovoltaic or a low emissivity coating, extending over and being adhered to a central region of an inner major surface of a first substrate, which first substrate opposes a second substrate whose inner surface includes a central region facing the functional coating; the first and second substrates are joined together by a spacer member, which is directly adhered to aligned peripheries of the inner major surfaces of the first and second substrates, such that an airspace is enclosed between the central regions of the first and second substrates. The spacer member is preferably formed from a material having properties that result in a moisture vapor transmission rate therethrough of no greater than approximately 20 g mm/m 2 /day, in an environment characterized by a relative humidity of approximately 100% and a temperature of approximately 38° C., and as measured per ASTM F 1249. 
     According to some embodiments, the spacer member is pre-formed, for example, via injection molding, to have a footprint that matches a shape of the periphery of each of the first and second substrates, so that, according to preferred methods of the present invention, the spacer member may simply be placed, or sandwiched, between the peripheries of the first and second substrates, and then adhered directly thereto, for example, by, first, heating the first and second substrates and, then, pressing the substrates toward one another. According to some alternate embodiments, the spacer member includes pre-formed strips that come together at a corner of each periphery in one of: a miter joint, an overlap joint and an interlocking joint. According to some preferred embodiments, the material from which the spacer member is formed is an ethylene methacrylic acid copolymer, and a silane primer is applied to the periphery of each of the first and second substrates in order to enhance the adhesion of the spacer member thereto. 
     Some embodiments of the present invention further include a support member that is disposed between the central regions of the first and second substrates and, preferably, has a thickness to span the airspace therebetween. In those embodiments, which include an opening formed through the central region of second substrate, the support member may surround at least a portion of a perimeter of the opening. The opening may be used for routing a lead wire out from the airspace, for example, in those embodiments in which the functional coating is a photovoltaic coating. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are illustrative of particular embodiments of the present invention and therefore do not limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements. 
         FIG. 1  is a perspective view of a glazing assembly, according to some embodiments of the present invention. 
         FIG. 2  is a schematic plan view of either of the substrates of the assembly shown in  FIG. 1 . 
         FIG. 3A  is a perspective view of a portion of the assembly shown in  FIG. 1 , according to some embodiments of the present invention. 
         FIGS. 3B-E  are plan views of portions of the assembly shown in  FIG. 1 , according to some alternate embodiments. 
         FIGS. 4-6  are section views through line A-A of  FIG. 1 , according to various embodiments of the present invention. 
         FIG. 7A  is a chart presenting a first set of adhesion test results. 
         FIG. 7B  is a chart presenting a second set of adhesion test results. 
         FIG. 8A  is a cross-section of a portion of a coated substrate of any of the assemblies shown in  FIGS. 4-6 . 
         FIG. 8B  is a perspective view of a portion of any of the assemblies shown in  FIGS. 4-6 , according to some further embodiments. 
         FIGS. 9A-B  are perspective views of a portion of a glazing assembly, according to some alternate embodiments of the present invention. 
         FIGS. 10A-C  are perspective views of a portion of a glazing assembly, according to yet further embodiments of the present invention. 
         FIG. 11  is a schematic describing a portion of a production line, on which some method or assembly steps of the present invention may be carried out. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the present invention. 
       FIG. 1  is a perspective view of a glazing assembly  10 , according to some embodiments of the present invention.  FIG. 1  illustrates assembly  10  including a first panel, or substrate  11 , a second panel, or substrate  12  and a spacer member  15 , which is disposed between first substrate  11  and second substrate  12  and which joins substrates  11 ,  12  together; a first, or inner major surfaces  121  of substrates  11 ,  12  face inward, or toward one another, being spaced apart from one another by spacer member  15 , and second, or outer major surfaces  122  of substrates  11 ,  12 , face outward, or away from one another. First and second surfaces  121 ,  122  of each substrate  11 ,  12  may be more clearly seen in the section views of  FIGS. 4-6 . According to the illustrated embodiment, first substrate  11  is transparent, or light transmitting, for example, formed from glass or a plastic material, such as polycarbonate, and second substrate  12  may be similarly formed, according to some embodiments, but may be opaque according to some alternate embodiments. Although the term “glazing” typically connotes incorporation of a glass panel or substrate, the use of the term is not so limited in the present disclosure, and glazing assemblies of the present invention may incorporate any transparent, or light transmitting substrate, for example, formed from a plastic such as polycarbonate. Further, while the embodiments illustrated in the figures of the present application are depicted with generally rectangular or square shaped substrates, it will be understood that in other embodiments the assembly may be provide with different shapes, e.g. circular or triangular. 
       FIG. 2  is a schematic plan view of either of the substrates  11 ,  12  of assembly  10 .  FIG. 2  illustrates inner major surface  121  of substrate  11 / 12  having a central region  108  and a periphery  105 , which are delineated from one another by the dashed line. With reference to  FIGS. 1 and 2 , in conjunction with  FIG. 3A , which is a perspective view of assembly  10  having first substrate  11  removed, it may be appreciated that spacer member  15  joins first substrate  11  to second substrate  12  along periphery  105  of each, which are aligned with one another.  FIG. 3A  illustrates an airspace  200  that extends between inner surfaces  121  of the joined substrates  11 ,  12 . The term airspace, as used herein, is intended to encompass a space that is filled with any type of gas, not only air.  FIG. 3A  further illustrates spacer member  15  having a thickness t, which, according to preferred embodiments of the present invention, is between approximately 0.01 inch and approximately 0.1 inch, but could be up to 1 inch in alternate embodiments. 
       FIG. 3A  further illustrates second substrate including optional openings  18 , one or both of which may be included in various embodiments. Openings  18 , which are shown formed in second substrate  12 , may be used to fill airspace  200  with another gas and/or to draw vacuum between joined substrates  11 ,  12 , and/or to dispense a desiccant material into airspace  200 . Other secondary manufacturing operations, that are performed within airspace  200 , for example, as described below, in conjunction with the embodiment that includes the functional coating of  FIG. 8A , may be facilitated by the inclusion of at least one opening  18  in second substrate  12 , or opening  19  in spacer member  15 . 
     According to preferred embodiments of the present invention, spacer member  15  is formed from a polymer material having low moisture vapor transmission properties, for example, resulting in a moisture vapor transmission rate (MVTR) therethrough of no greater than approximately 20 g mm/m 2 /day, in an environment characterized by a relative humidity of approximately 100% and a temperature of approximately 38° C., and as measured per ASTM F 1249. Examples of such suitable materials include, without limitation, ionomers, ethylene methacrylic acid copolymers and polyisobutylenes, the ethylene methacrylic acid copolymers being preferred for their excellent adhesion properties, which are desirable to hold together glazing assemblies such as assembly  10 . Some examples of these preferred materials, which are commercially available, are Sentry Glas®Plus, available from DuPont, and PRIMACOR™, available from Dow Chemical. 
     According to some preferred embodiments, spacer member  15  is pre-formed to have a footprint that matches a shape of peripheries  105 . In  FIG. 3A  spacer member  15  is shown as a four-sided pre-formed member, for example, having been injection molded, or cut out from an extruded or molded sheet of material; the four sides of spacer member  15  extend along first, second, third and fourth straight edges  101 ,  102 ,  103 ,  104  of periphery  105  of each substrate  11 ,  12  ( FIG. 2 ), and the sides are continuous around corners  112  of the intersecting edges. Of course, alternate shapes of peripheries and the corresponding pre-formed footprints of spacer members are within the scope of the present invention. According to alternate embodiments, each side of spacer member  15  may be independently formed as a strip, for example, via extrusion, molding or cutting from an extruded or molded sheet of material. 
       FIGS. 3B-E  are plan views of alternate corner portions of assembly  10 , which illustrate the sides of spacer member  15 , which are each independently formed, coming together at corners  112 , according to the alternate embodiments.  FIG. 3B  illustrates a first pre-formed spacer member strip  151  and a second pre-formed spacer member strip  152  coming together at corner  112  in a miter joint  31 .  FIG. 3C  illustrates a first pre-formed spacer member strip  153  and a second pre-formed spacer member strip  154  coming together at corner  112  in a overlap joint  32 , wherein strip  153  overlaps strip  154 .  FIG. 3D  illustrates a first pre-formed spacer member strip  155  and a second pre-formed spacer member strip  156  coming together at corner  112  in an interlocking “puzzle piece” joint  33 .  FIG. 3E  illustrates a first pre-formed spacer member strip  157  and a second pre-formed spacer member strip  158  coming together at corner  112  in an interlocking “dove tail” joint  34 . 
     Embodiments of the present invention further include a coating extending over one or both major surfaces  121 ,  122  of either or both substrates  11 / 12 . According to some preferred embodiments, inner major surface  121  of first substrate  11  bears a coating, for example a low emissivity coating, known to those skilled in the art, or a photovoltaic coating, various embodiments of which are also known to those skilled in the art. The extent of a coating borne by inner surface  121  of first substrate  11 , with respect to an extent of spacer member  15 , may vary according to various embodiments, examples of which are illustrated in  FIGS. 4-6 .  FIGS. 4-6  are section views through line A-A of  FIG. 1 , according to various embodiments of the present invention.  FIG. 4  illustrates a coating  42  disposed over only central region  108  ( FIG. 2 ) of inner surface  121  of substrate  11 , and spacer member  15  extending over only periphery  105  ( FIG. 2 ) of inner surface  121 .  FIG. 5  illustrates an alternate embodiment wherein spacer member  15  further extends over a portion of central region  108 , and over an edge portion  420  of coating  42 , which edge portion  420  is located adjacent to periphery  105 .  FIG. 6  illustrates another alternate embodiment, wherein a coating  42 ′ is disposed over both central region  108  and periphery  105 , of inner surface  121  of substrate  11 , so that spacer member  15  extends over a portion of coating  42 ′. 
     With further reference to  FIGS. 4-6 , a dashed line schematically represents an optional desiccant material, which is enclosed within airspace  200  to absorb any moisture that may pass through spacer member  15 . The desiccant material, either in sheet or strip form, or granular form, either embedded in a matrix or packaged in a sack, may be ‘free-floating’ in airspace  200 , or adhered to one of substrates  11 ,  12 , or otherwise present in airspace  200 . 
     Spacer member  15  may adequately adhere to both the native inner surfaces  121  of substrates  11 ,  12  and to any of the materials that may form coating  42 ,  42 ′, in order to join first and second substrates  11 ,  12  together for the various embodiments described above. However, according to some preferred embodiments, in which spacer member  15  is formed from an ethylene methacrylic acid copolymer, for example, the Sentry Glas®Plus material, and in which substrates  11 ,  12  are formed from glass, peripheries  105  are pre-treated with a silane primer, which activates surfaces  121  and thereby enhances the adhesion of spacer member  15  thereto. This enhanced adhesion promotes hydrolytic stability, which is desirable for those applications in which the outer edges of assembly  10  are exposed to the elements, for example, when assembly  10  includes a photovoltaic coating and serves in the capacity of a solar cell. 
     The use of silane primers to enhance adhesion to glass substrates is known in the art, but there are numerous possible formulations of these primers and the efficacy of a particular formulation depends on various attributes of assembly  10 . Therefore, several formulations of silane primers, comprising the silane mixtures described in TABLE 1, below, were evaluated for application to some embodiments of the present invention. 
                                 TABLE 1                           Primer       Silane Mixture %   Primer 1   Primer 2   3                                                Glycidoxypropyl Trimethoxysilane   65.2%               (Dow Corning Z-6040)       Methacryloxypropyl Trimethoxysilane       65.2%   75.0%       (Dow Corning Z-6030)       Isobutyl Trimethoxysilane   21.7%   21.7%       (Gelest SII 6453.7)       Vinyltrimethoxysilane           25.0%       (Gelest SIV 9220.0)       Bis (triethoxysilyl) ethane   13.0%   13.0%       (Gelest SIB 1817.0)           Total   100.0%   100.0%   100.0%                    
The Primers 1-3 were formulated by combining each of the above silane mixtures (% by weight), in a 2% concentration, by volume, with a corresponding mixture of 95% ethanol and 5% water (by volume), in which the pH had been adjusted to between approximately 4.5 and approximately 5.5 with acetic acid. Each of Primers 1-3 were sprayed onto, and then wiped off from, cleaned surfaces (tin-side) of corresponding glass substrates; each substrate surface had been cleaned with a 50-50 mixture of Isopropyl Alcohol (IPA) and reverse osmosis-filtered (RO) water. Approximately one day after primer application, three sample groups of single-sided laminates were formed, one group for each of Primers 1-3, by adhering an extruded sheet of the Sentry Glas®Plus material (DuPont SGP) to each treated surface of the glass substrates in each group. Each sample was assembled, generally, as follows: an extruded sheet of DuPont SGP was sandwiched between a silane treated side of a first glass substrate and another glass substrate, with a release liner interposed between the other substrate and the SGP; a high temperature tape was used to hold each sample together while the samples were run through a series of ovens and nip rollers, for example, as is described below, in conjunction with  FIG. 11 ; then, the samples were placed in an autoclave in which temperature and pressure were ramped to, and held at, soaked, for about 1 hour, around 280° F. and around 180 psi, respectively; after the soak, the autoclave temperature and pressure were ramped down and the samples removed; and, finally, prior to evaluation, the second glass substrate and liner were removed leaving only the SGP adhered to the treated first glass substrate. A fourth, control, group of samples was also similarly prepared, wherein extruded sheets of DuPont SGP were adhered to non-treated glass substrates, rather than the treated substrates.
 
     The adhesion of samples from each of the three groups, along with samples from the control group, in which no primer was applied, were peel tested using a fracture mechanics, constant load test method, which is described in: “Measuring and Predicting Sealant Adhesion” PhD Dissertation by Nick E. Shephard (J. P. Wightman), April 1995, Virginia Tech, Center for Adhesive and Sealant Science; and in “A simple device for measuring adhesive failure to sealant joints” by Shephard, N. E. and Wightman, J. P., which is found in: Klosowski, J. M. (Ed.), Science and Technology of Building Seals, Sealants, Glazing, and Waterproofing, Seventh Volume, ASTM STP 1334. American Society for Testing and Materials, Philadelphia, Pa., 1998. The test method provides an indication of adhesion durability by concentrating a load on an adhesive crack tip and measuring the resulting crack growth rate. Testing parameters employed for samples from each of the groups, and the corresponding results are shown in the chart of  FIG. 7A . With reference to  FIG. 7A , it may be appreciated that Primer 1 significantly enhanced adhesion, while Primers 2 and 3 do not significantly improve adhesion over that measured for samples in the control group. Chemical formulas for each constituent of Primer 1 are as follows: 
     (3-Glycidoxypropyl) trimethoxysilane: CH 2 OCHCH 2 OCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ;
 
Isobutyl trimethoxysilane: (CH 3 ) 2 CHCH 2 Si(OCH 3 ) 3 ; and
 
     Bis(triethoxysilyl)ethane: (CH 3 CH 2 O) 3 SiCH 2 CH 2 Si(OCH 2 CH 3 ) 3 . 
     It should be noted that it is anticipated that the “ethoxy form” of each the first two listed constituents of Primer 1: (3-glycidoxypropyl) triethoxysilane (CH 2 OCHCH 2 OCH 2 CH 2 CH 2 Si(OCH 2 CH 3 ) 3 ; commercially available as Gelest 5839.0), and Isobutyl triethoxysilane ((CH 3 ) 2 CHCH 2 Si(OCH 2 CH 3 ) 3 ; commercially available as Gelest SII 6453.5), may be substituted for the “methoxy form” of each of these in the above described formulation of Primer 1, without compromising the adhesion enhancement found with Primer 1. The ethoxy form of the third constituent, Bis(triethoxysilyl)ethane, is preferred to the methoxy form thereof, Bis(trimethoxysilyl)ethane ((CH 3 O) 3 SiCH 2 CH 2 Si(OCH 3 ) 3 ; commercially available as Gelest SIB 1830.0), due to the potential inhalation hazard posed by the methoxy form. 
     In order to determine a viable range for each silane constituent of Primer 1, a designed experiment was conducted according to the plan outlined in TABLE 2. 
                                                                 TABLE 2               Silane Mixture %   1   2   3   4   5   6   7   8   9   10   11                                                                                Glycidoxypropyl   65.2%     100%           50%   50%    0%   33.3%   66%   17%   17%       Trimethoxysilane       (Dow Corning Z-6040)       Isobutyl   21.7%         100%       50%    0%   50%   33.3%   17%   66%   17%       Trimethoxysilane       (Gelest SII 6453.7)       Bis(triethoxysilyl)   100.0%             100%    0%   50%   50%   33.3%   17%   17%   66%       ethane       (Gelest SIB 1817.0)       Total   100.0%   100.0%   100.0%   100.0%   100.0%     100.0%     100.0%     100.0%   100.0%     100.0%     100.0%                      
Each variation of Primer 1, was formulated by combining each of the TABLE 2. silane mixtures (% by weight), in a 2%, by volume, concentration, with a corresponding mixture of 95% ethanol and 5% water (by volume), in which the pH had been adjusted to between approximately 4.5 and approximately 5.5, with acetic acid. Each of the eleven Primer 1 variations were sprayed onto, and then wiped off from, cleaned surfaces (tin-side) of corresponding glass substrates; each substrate surface had been cleaned with a 50-50 mixture of Isopropyl Alcohol (IPA) and reverse osmosis-filtered (RO) water. Approximately one day after primer application, eleven sample groups of single-sided laminates were formed, one group for each Primer 1 variation, in a manner similar to the sample assembly method described above for the initial evaluation of Primers 1-3.
 
     Peel testing, according to the above-described method, was performed on samples from each of the 11 groups, as well as on control samples. Test parameters and results are presented in the chart in  FIG. 7B , wherein the twelfth group of samples  12 - 2 ,  12 - 4  and  12 - 6 , are the control samples. With reference to  FIG. 7B , it may be appreciated that those variations of Primer 1, which included either of the silane constituents, Glycidoxypropyl trimethoxysilane or Bis (triethoxysilyl)ethane, alone or in combination with one or both of the other Primer 1 silane constituents, resulted in superior hydrolytically stable adhesion, compared with that of the group  3  Primer 1 variation (samples  3 - 2 ,  3 - 4 ,  3 - 12 ) and no primer. 
     According to some embodiments of the present invention, coating  42  or  42 ′ is a ‘thin film’ photovoltaic coating of any type known to those skilled in the art, for example, a thin film CdTe type, which is described below, in conjunction with  FIG. 8A , a thin film Cu(InGa)Se 2  (CIGS) type, or an amorphous silicon (a-Si) type. According to preferred embodiments of the present invention, which include the photovoltaic coating, the aforementioned desiccant material, which is enclosed within airspace  200 , in combination with the aforementioned relatively low MVTR of spacer member  15 , effectively prevents moisture build-up within airspace  200  that can lead to corrosion of certain elements of the photovoltaic coating. With reference to  FIG. 8A , according to some preferred embodiments, a sheet-like material  755 , to which a plurality of desiccant beads are adhered, is adhered to a photovoltaic coating  700 . According to alternate embodiments, desiccant material  755  may be adhered to the opposing substrate  12 . It should be noted that some embodiments of the present invention may include a flexible and electrically non-conductive film extending over approximately an entirety of photovoltaic coating  700 , such that coating  700  is sandwiched between the film and substrate  11 , for example, as is described in commonly assigned and co-pending U.S. patent application, which is entitled: GLAZING ASSEMBLIES THAT INCORPORATE PHOTOVOLTAIC ELEMENTS AND RELATED METHODS OF MANUFACTURE, has the Ser. No. 12/167,826, and is hereby incorporated, by reference, in its entirety. 
       FIG. 8A  is a cross-section of substrate  11  bearing photovoltaic coating  700  over inner surface  121 .  FIG. 8A  illustrates coating  700  including a first layer  701  formed by a transparent conductive oxide (TCO), for example, comprising Tin oxide (SnO 2 ), which is overlaid with a semiconductor layer  702 , for example, comprising two ‘sub-layers’: Cadmium sulfide (CdS; ‘window’ layer; n-type), extending adjacent to first layer  701 , and Cadmium Telluride (CdTe; absorbing layer; p-type), overlaying the Cadmium sulfide sub-layer.  FIG. 8A  further illustrates an electrical contact layer  703 , for example, comprising nickel, which extends between the Cadmium Telluride sub-layer of semiconductor layer  702  and a pair of bus bars  704 . Bus bars  704  may each be formed from a copper tape, for example, approximately 0.003-0.007 inch thick, which are adhered to contact layer  703 , for example, by conductive acrylic adhesive. Bus bars  704  preferably extend approximately parallel to one another along opposing edge portions of coating  700  and electrical lead wires  76  ( FIG. 8B ) are coupled bus bars  704  for powering of assembly  10  as a solar cell. Lead wires  76  may be routed out from between substrates  11 ,  12  through one of openings  18  ( FIG. 3A ), or out through spacer member  15 , for example, as is illustrated in  FIG. 8B . 
       FIG. 8B  is a perspective view of a portion of a glazing assembly, for example, similar to assembly  10  of  FIG. 1 , wherein spacer member  15  is pre-formed to include lead wires  76  extending therethrough, for example, via insert injection molding.  FIG. 8B  illustrates each of lead wires  76  including an inner terminal end  71  coupled to the corresponding bus bar  704  of coating  700 , within airspace  200 , and each of lead wires  76  including an outer terminal end  760 , which are accessible outside of airspace  200 . According to the illustrated embodiment, inner terminal ends  71  are be coupled to bus bars  704  prior to affixing first and second substrates  11 ,  12  to spacer member  15 , and then outer terminal ends  760  may be coupled to a power source upon installation of the completed glazing assembly. Thus, opening(s)  18  ( FIG. 3A ) are not necessary for embodiments of glazing assemblies that include the wire routing illustrated in  FIG. 8B , nor for yet another wire routing embodiment in which the lead wires are passed out from airspace  200  between spacer member  15  and first substrate  11 , for example, as illustrated with dashed lines in  FIG. 8B . According to additional alternate embodiments, spacer member  15  includes a pre-formed opening  19  ( FIG. 3A ) through which lead wires may be routed; and, according to yet further alternate embodiments, lead wires may be routed by piercing through spacer member  15 , or by extending alongside spacer member  15 , between spacer member  15  and substrate  11 , as mentioned above. 
       FIGS. 9A-B  are perspective views of a portion of a glazing assembly, for example, similar to assembly  10 , shown in  FIG. 1 , wherein first substrate  11  is removed for clarity in illustration.  FIGS. 9A-B  present some alternate embodiments of support members that can provide additional stability to the spacing between substrates  11 ,  12 , which is established by spacer member  15 ; the support members can also control other features of the assembly, as is further described below. 
       FIG. 9A  illustrates the assembly including a pair of support members  81 , each of which, preferably, has a thickness, like spacer member  15 , to span airspace  200  between first substrate  11  and second substrate  12 .  FIG. 9A  further illustrates support members  81  surrounding a portion of a perimeter of opening  18 .  FIG. 9B  illustrates the assembly including a support member  82 , which also has a thickness, like spacer member  15  and support members  81  of  FIG. 9A , to span airspace  200 , but which completely surrounds the perimeter of opening  18 . According to the illustrated embodiments, after opening  18  has provided access to airspace, for example, for performing any of the aforementioned secondary operations, a potting material  800  may be applied to seal off opening  18 , in which case, either of support members  81 ,  82  can provide a barrier to control the flow of potting material  800 , and thereby limit an extent of material  800  over inner surface  121  of each of substrates  11 ,  12 . As previously described, opening  18  may further provide a passageway for routing lead wires that are coupled to photovoltaic coating  700  ( FIG. 8A-B ); according to these embodiments, potting material  800  is applied around the lead wires within opening  18 . According to some preferred embodiments, support members  81 ,  82  are formed from a low MVTR material, for example, selected from the same group previously described for spacer member  15 . With reference to  FIG. 9B , it may be appreciated that support member  82 , being formed of the preferred material, can function to further seal airspace  200  from moisture ingress through opening  18 . Although support members  81 ,  82  are shown being formed as separate members from spacer, according to alternate embodiments, support members  81 ,  82  are integrally pre-formed with spacer member  15 , for example, via injection molding. 
       FIGS. 10A-C  present some additional alternate embodiments of support members, which provide additional stability to the spacing between substrates  11 ,  12 .  FIGS. 10A-C  illustrate support members  751 ,  752  and  753 , respectively, each, preferably, having a thickness similar to that of spacer member  15 , to span airspace.  FIG. 10A  shows support member  751  extending from one side to another of spacer member  15 ;  FIG. 10B  shows support member  752  extending diagonally between opposing corners of spacer member  15 ; and  FIG. 10C  shows support member  753  being centrally located and independent of spacer member  15 . Any of support members  751 ,  752 ,  753  may be incorporated in assembly  10 , in combination with either of support members  81 ,  82 , which were previously described in conjunction with  FIGS. 9A-B . Each of support members  751 ,  752 ,  753  may be formed from the same material that forms spacer member  15 . According to some embodiments, either of support members  751  and  752  may be integrally formed with spacer member  15 , for example, via injection molding, or may be formed from independent strips of material. For those embodiments in which support members divide airspace  200  into sub-compartments, for example, member  751  or member  752 , an opening, such as opening  78  shown in  FIG. 10A , is preferably formed through a portion of the support member to provide for fluid communication between the sub-compartments, for example, so that desiccant material need not be separately placed in each sub-compartment. 
     Some methods for making glazing assembly  10 , as generally shown in  FIG. 1 , and according to any of the alternative embodiments, which are described in conjunction with  FIGS. 1-10C , will now be described. Initially, a pair of panels, or substrates, for example substrates  11 ,  12 , are formed according to methods well known in the art. Formation of at least one of the substrates includes a step of coating a major surface of the substrate. According to some preferred methods, the major surface of one of the substrates, which will face a major surface of the other substrate in the glazing assembly, for example, first, or inner surface  121  of first substrate  11 , is coated with either a low emissivity coating or a photovoltaic coating, according to methods known to those skilled in the art. 
     The initial substrate formation may further include a step of forming at least one opening through one or both of the substrates, but preferably, just through the substrate which does not include the coating. According to some preferred methods, initial substrate formation further includes a step in which a desiccant material is adhered to that surface, of one or both of the substrates, which will be the inner surface of the assembly, for example, as previously described in conjunction with  FIG. 8A . When the coating is a photovoltaic coating, for example, coating  700  ( FIG. 8A ), lead wires, for example, wires  76  ( FIG. 8B ), are preferably attached at this time too. 
     According to preferred methods, either prior to, during, or following substrate formation, a spacer member, for example, spacer member  15 , is formed, either via extrusion or molding, from a low MVTR material. The spacer member may be cut from a pre-extruded sheet of material, and the left over portions of the sheet recycled, or, preferably, the spacer member is injection molded. The spacer member is then sandwiched between the facing surfaces of the pair of substrates, along aligned peripheries thereof, while maintaining an airspace between the facing surfaces. When the spacer member is sandwiched between the substrates, one or more support members, for example, any of support members  81 ,  82 ,  751 ,  752 ,  753 , having approximately the same thickness as the spacer member, may also be sandwiched between the substrates. Following the sandwiching, according to some preferred methods of the present invention, heat and pressure are applied to adhere, or affix the spacer member, and the support member(s), if included, to the facing surfaces of the pair of substrates in order to form a coherent assembly, for example, assembly  10 , which still includes an airspace, such as airspace  200 . 
     According to some methods, a primer is formulated, preferably to include one or more silane constituents, and then applied, for example, according to the method previously described, to the peripheries of the major surfaces to which the spacer member is adhered, in a step that precedes that in which spacer member is sandwiched. It should be noted that the primer may be applied to more than just the peripheries of the surfaces, for example, to central regions as well, so that process controls need not be employed to limit the application of the primer to only the peripheries, although some methods of the invention may do so. According to some preferred embodiments, the primer includes one or more of the silane constituents, presented above, in any of the mixtures, described above, for example, for Primer 1, or any of the eleven variations thereof. 
     Turning now to  FIG. 11 , a portion of an exemplary production line  900  for applying the aforementioned heat and pressure will now be described. Portions of  FIG. 11  have been borrowed from commonly assigned U.S. Pat. No. 7,117,914, which describes such a production line in detail, and those portions of the &#39;914 patent that describe the production line, are hereby incorporated by reference.  FIG. 11  schematically illustrates assembly  10  being conveyed, on rollers  928 , along a path  96  that travels through at least two ovens  990 ,  995 ; a pair of confronting press members  92 , which are embodied as nip rollers, are located along path  96  between ovens  990 ,  995 . According to the illustrated embodiment, oven  990 , which is the first oven of production line  900 , heats assembly  10 , as it is conveyed therethrough, to a temperature, preferably between approximately 200° F. and approximately 300° F.; heated assembly  10  is then delivered between confronting press members  92 , which apply a pressure to press substrates  11 ,  12  toward one another, and then assembly  10  is conveyed through oven  995 , which re-heats assembly  10  to a temperature, preferably between approximately 200° F. and approximately 300° F. Although not shown in  FIG. 11 , a preferred production line further includes another pair of press members  92 , which are located downstream of oven  955  to provide a second application of pressure to assembly  10 . 
       FIG. 11  further illustrates each member  92  including a rigid cylinder  904  that has a diameter  98 ; cylinder  904  is overlaid with a relatively soft cover  906  that has a thickness  901 . An outer surface  902  of cover  906  is preferably textured in a pattern similar to that of an automobile tire tread; exemplary materials and texture patterns for cover  906  are described in detail in the aforementioned &#39;914 patent. Press members  92  are shown spaced apart from one another in order to form a gap  946  through which assembly  10  travels as assembly  10  is conveyed along path  96 ; gap  946  is preferably smaller than an overall thickness  948  of assembly  10  so that confronting press members  92  can apply the pressure necessary to adhere/affix substrates  11 ,  12  to spacer member  15 . Gap  946  may be varied, for a given thickness of assembly  10 , according to a durometer of cover  906 , the softer the cover, the smaller the gap. The second set of confronting press members  92 , not shown, but previously described as being downstream of oven  955 , are preferably spaced apart by a gap that is smaller than gap  946 . 
     The preferred temperature ranges, which are indicated above, are applicable to preferred low MVTR materials, in particular, the Sentry Glas®Plus material. For this material and the preferred temperature ranges, a rate of transport for glazing assemblies, like assembly  10 , through production line  900  may be between approximately 10 feet/minute and approximately 20 feet/minute. It should be noted that, although production line  900  has been found to provide good operating efficiency for relatively large volume production of assemblies, such as assembly  10 , the scope of the present invention is not limited by any particular production process for adhering/affixing substrates  11 ,  12  to spacer member  15 . Other suitable processes, which are known in the art, include vacuum lamination processes, for example, either those employing clam shell-type fixturing or an autoclave. 
     According to those embodiments that include one or more openings, for example, openings  18 ,  19  ( FIG. 3A ), after substrates  11 ,  12  are adhered to spacer member  15 , the opening(s) may be used to perform secondary operations related to an airspace, for example, airspace  200 . Examples of these secondary operations, include, without limitation, dispensing a desiccate material into airspace  200 , in addition to, or as an alternative to, adhering the desiccant, as previously described, filling airspace  200  with a gas, and pulling vacuum in airspace  200 . According to those embodiments that include a photovoltaic coating, for example, those described in conjunction with  FIGS. 7A-B , lead wires, which are coupled to the coating, may be routed out through the opening, either prior to the adhering/affixing process, for example, in conjunction with the sandwiching step, or following the adhering/affixing process. However, according to the aforementioned alternate embodiments, the coupled lead wires are routed out through spacer member  15 , for example, as previously described in conjunction with  FIG. 8B . A diameter of opening(s)  18  may be between approximately ¼ inch and approximately 1 inch in order to accommodate these secondary operations. For those embodiments including opening(s)  18 , and/or opening  19 , the opening(s), are sealed off with a potting material after the secondary operations are completed. If substrate  12  bears a photovoltaic coating, along an inner, or first surface  121  thereof, and lead wires extend through the one or more openings, then the potting material is applied around the lead wires, to seal off the opening. Examples of suitable potting materials include, without limitation, polyurethane, epoxy, polyisobutylene, and any low MVTR material; according to some embodiments, the same material which forms spacer member  15  may be used for the potting material. 
     In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention as set forth in the appended claims.