Abstract:
This invention is related to the production of glasses having compositions within the copper and/or silver-halide-phosphate field, wherein at least one halide is present selected from the group of fluoride, chloride, bromide, and iodide, such glasses exhibiting softening points below about 400° C., coefficients of thermal expansion (25°-300° C.) in excess of about 180×10 -7  /°C., high electrical conductivity, and electrochromic behavior. The copper-containing glasses may also demonstrate thermochromic properties.

Description:
BACKGROUND OF THE INVENTION 
     Most inorganic glasses at room temperature typically demonstrate values of electrical resistivity well in excess of 10 8  ohm cm. However, it has long been recognized that a transparent membrane with high ionic conductivity would have considerable value. Thus, glasses with low electrical resistivities can have utility in electrochemical devices which demand high ionic conductivity. 
     The high ionic conductivity of copper and silver ions is well-known and glasses containing those ions have been formulated. Nevertheless, this prior research has not fully exploited the full capability of such glasses. For example, such glasses may exhibit an electrochromic phenomenon due to the electrochemical reduction of the copper and/or silver ions to the respective metal. 
     SUMMARY OF THE INVENTION 
     The present invention is founded in the discovery that glasses having compositions within the copper and/or silver-halide-phosphate system, wherein at least one halide is selected from the group of fluoride, bromide, chloride, and iodide, can be produced which have low softening points, high coefficients of thermal expansion, and which may have high conductivity and exhibit electrochromic behavior. The copper-containing glasses may also demonstrate thermochromic characteristics. Thus, such glasses have softening points below 400° C. and, in some instances, below 150° C. The coefficients of thermal expansion (25°-300° C.) are generally in excess of 180×10 -7  /° C. and, hence, approximate those of certain metals. The glasses demonstrate electrical resistivities less than 10 8  ohm cm. at room temperature (˜25° C.), preferably less than 10 7  ohm cm, with certain compositions ranging down to less than 10 3  ohm cm. Finally, the glasses can exhibit electrochromism based upon their high ionic conductivity. 
     Electrochromism is the change in color of an electrode due to the passage of electric current. Color is typically produced electrochemically via the reduction of an ion to the metal at the cathode or a change in oxidation state of a colorless ion to a colored ion at the cathode or anode. In the darkened state the charge is stored electrochemically, i.e., the system is the charged state of a battery. Fading of the color is promoted by shorting the electrodes or by reversing the d.c. field. If the electrodes are shorted, the driving force for fading is the internal EMF of the battery and, consequently, will typically be slow. However, if a reverse field of the same magnitude as that utilized to cause darkening is applied, then fading will be more rapid than darkening since the internal EMF of the system adds to the applied EMF. 
     FIGS. 1, 2, and 3 constitute ternary composition diagrams illustrating the areas of stable glasses which have been produced in the Cu 2  O-CuCl-P 2  O 5 , the Cu 2  O-CuBr-P 2  O 5 , and the Cu 2  O-CuI-P 2  O 5  system, respectively. Hence, in each diagram, transparent, stable glasses exhibiting a light yellow to amber color and demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm are depicted within the area delimited ABCD expressed in weight percent as calculated from the batch. 
     In FIG. 1, points A, B, C, and D have the approximate values recited below: 
     
         A=0% Cu.sub.2 O, 70% CuCl, 30% P.sub.2 O.sub.5 
    
     
         B=40% Cu.sub.2 O, 30% CuCl, 30% P.sub.2 O.sub.5 
    
     
         C=20% Cu.sub.2 O, 30% CuCl, 50% P.sub.2 O.sub.5 
    
     
         D=0% Cu.sub.2 O, 50% CuCl, 50% P.sub.2 O.sub.5 
    
     Glass compositions containing less than 30% CuCl were quite dark in color and showed electrical resistivities in excess of 10 8  ohm cm. Compositions wherein the P 2  O 5  content exceeded 50% were poorly durable and also exhibited electrical resistivities greater than 10 8  ohms. Compositions having less than 30% P 2  O 5  proved to be unstable with regard to devitrification. As can be seen, good stable glasses of high conductivity can be formed on the CuCl-P 2  O 5  binary. 
     In FIG. 2, points A, B, C, and D have the approximate concentrations reported below in weight percent: 
     
         A=0% Cu.sub.2 O, 70% CuBr, 30% P.sub.2 O.sub.5 
    
     
         B=50% Cu.sub.2 O, 20% CuBr, 30% P.sub.2 O.sub.5 
    
     
         C=40% Cu.sub.2 O, 10% CuBr, 50% P.sub.2 O.sub.5 
    
     
         D=0% Cu.sub.2 O, 50% CuBr, 50% P.sub.2 O.sub.5 
    
     Most of these glasses appeared to be somewhat lighter in color than the corresponding glasses containng CuCl. This phenomenon is believed to indicate less sensitivity to redox conditions in the melt. The same parameters were used to judge satisfactory glasses as were used with the CuCl-containing glasses. Acceptable glasses were found at higher Cu 2  O levels than were seen in the Cu 2  O-CuCl-P 2  O 5  system. 
     In the FIG. 3, points A, B, C, and D have the following approximate compositions in weight percent: 
     
         A=0% Cu.sub.2 O, 70% CuI, 30% P.sub.2 O.sub.5 
    
     
         B=50% Cu.sub.2 O, 20% CuI, 30% P.sub.2 O.sub.5 
    
     
         C=40% Cu.sub.2 O, 10% CuI, 50% P.sub.2 O.sub.5 
    
     
         D=0% Cu.sub.2 O, 50% CuI, 50% P.sub.2 O.sub.5 
    
     The composition ranges of suitable glasses were found to be essentially identical to those of the CuBr-containing glasses. Again, the same parameters were utilized to judge acceptable glasses as were used with the CuCl-containing glasses. In like manner to the CuBr and CuCl-containing glasses, good stable glasses demonstrating low electrical resistivities were found on the CuI-P 2  O 5  binary. 
     It will be appreciated, of course, that a combination of two or three halides, may be present in the glass compositions. 
     FIG. 4 illustrates that feature in that it constitutes a ternary composition diagram setting forth an area of stable glasses, expressed in terms of mole percent, demonstrating electrical resitivities at 25° C. of less than 10 8  ohm cm which have been formed in the Cu 2  O-P 2  O 5  -X system wherein X is at least one halide selected from the group of Cl, Br, and I. Points A, B, and C have the following approximate compositions in mole percent: 
     
         A=35% Cu.sub.2 O, 50% P.sub.2 O.sub.5, 15% X 
    
     
         B=55% Cu.sub.2 O, 30% P.sub.2 O.sub.5, 15% X 
    
     
         C=35% Cu.sub.2 O, 30% P.sub.2 O.sub.5, 35% X 
    
     The center of the scribed triangle is a point having the molecular formula Cu 2  O·P 2  O 5  ·1/2X, where X is one or more of the group Cl, Br, and I. 
     FIGS. 5, 6, 7, 8, 9, 10, and 11 represent ternary composition diagrams illustrating the areas of stable glasses demonstrating electrical resistivities at 25° C. of less than 10 8  ohm cm which have been formed in the Ag 2  O-AgCl-P 2  O 5 , the Ag 2  O-AgBr-P 2  O 5 , the Ag 2  O-AgI-P 2  O 5 , the Cu 2  O-P 2  O 5  -F, the Cu 2  O-P 2  O 5  -Cl/F, the Cu 2  O-P 2  O 5  -Br/F, and the Cu 2  O-P 2  O 5  -I/F system, respectively. 
     In FIG. 5, points A, B, C, and D have the approximate values set out below in weight percent: 
     
         A=42% Ag.sub.2 O, 46% AgCl, 12% P.sub.2 O.sub.5 
    
     
         B=73% Ag.sub.2 O, 3% AgCl, 24% P.sub.2 O.sub.5 
    
     
         C=52% Ag.sub.2 O, 3% AgCl, 45% P.sub.2 O.sub.5 
    
     
         D=30% Ag.sub.2 O, 46% AgCl, 24% P.sub.2 O.sub.5 
    
     Although glasses free from chloride can be prepared which are ionic conducting and electrochromic, the durability and electrical conductivity thereof are significantly improved through the addition of chloride to the composition. Accordingly, a finite amount of chloride will be incorporated into the glass composition effective to improve those properties. In general, chloride in an amount of at least 1% will be included in the composition (1% Cl≡3% AgCl) with at least 5% being preferred. 
     Glasses within the area ABCD vary in color from colorless to a pale yellow, are quite fluid, can exhibit electrochromic behavior, and soften at temperatures between about 200°-400° C. Rather rapid cooling of the individual melts was necessitated since several thereof tended to devitrify upon slow cooling. Compositions containing excessive amounts of P 2  O 5  formed glasses which were poorly durable and demonstrated electrical resistivities greater than 10 8  ohm cm. The presence of Ag 2  O and/or AgCl in high quantities reduces the stability of the glass against devitrification. 
     In FIG. 6, points A, B, C, and D have the approximate values reported below in weight percent: 
     
         A=36% Ag.sub.2 O, 56% AgBr, 8% P.sub.2 O.sub.5 ps 
    
     
         B=74% Ag.sub.2 O, 2% AgBr, 24% P.sub.2 O.sub.5 
    
     
         C=54% Ag.sub.2 O, 2% AgBr, 44% P.sub.2 O.sub.5 
    
     
         D=24% Ag.sub.2 O, 56% AgBr, 20% P.sub.2 O.sub.5 
    
     Similarly to the AgCl-containing glasses discussed above, bromide is incorporated into the composition in an effective amount, usually at least about 1% (1% Br≡2% AgBr) with a minimum of 5% being preferred, to improve the durability and electrical conductivity of the glass. The glasses within area ABCD were pale yellow in color and, like the AgCl-containing glasses above, can exhibit electrochromic behavior, are quite fluid, and soften at temperatures below about 400° C. The same parameters were used to judge acceptable glasses as were used with the AgCl-containing glasses. Higher Ag 2  O levels were found operable than were seen in the Ag 2  O-AgCl-P 2  O 5  system glasses. 
     In FIG. 7, points A, B, C, D, and E have the following approximate compositions in weight percent: 
     
         A=16% Ag.sub.2 O, 70% AgI, 14% P.sub.2 O.sub.5 
    
     
         B=35% Ag.sub.2 O, 60% AgI, 5% P.sub.2 O.sub.5 
    
     
         C=74.5% Ag.sub.2 O, 1.5% AgI, 24% P.sub.2 O.sub.5 
    
     
         D=53.5% Ag.sub.2 O, 1.5% AgI, 45% P.sub.2 O.sub.5 
    
     
         E=16% Ag.sub.2 O, 40% AgI, 44% P.sub.2 O.sub.5 
    
     In like manner to the AgCl-containing glasses, iodide is included in the composition in an effective amount, typically at least about 1% (1% I≡1.5% AgI) with at least 5% being preferred, to enchance the durability and electrical conductivity of the glass. The glasses within area ABCDE were a darker yellow than the AgBr-containing compositions. Glasses still higher in AgI content were found to exhibit good ionic conductivity but were very dark brown in color and/or darkened in visible light. The same parameters were employed to judge satisfactory glasses as were used with the AgCl-containing glasses. Concentrations of AgI higher than either AgCl or AgBr are operable in the invention. 
     In FIG. 8, points A, B, C, D, and E have the following approximate compositions in weight percent: 
     
         A=90% P.sub.2 O.sub.5, 9% Cu.sub.2 O, and 1% F 
    
     
         B=69% P.sub.2 O.sub.5, 30% Cu.sub.2 O, and 1% F 
    
     
         C=50% P.sub.2 O.sub.5, 30% Cu.sub.2 O, and 20% F 
    
     
         D=50% P.sub.2 O.sub.5, 15% Cu.sub.2 O, and 35% F 
    
     
         E=62% P.sub.2 O.sub.5, 3% Cu.sub.2 O, and 35% F 
    
     
         F=90% P.sub.2 O.sub.5, 3% Cu.sub.2 O, and 7% F 
    
     Glass compositions containing more than 90% P 2  O 5  were so poorly durable as to be essentially useless from a practical point of view, whereas when less than 50% P 2  O 5  was utilized the glasses were difficult to melt and/or unstable with respect to devitrification. The presence of fluoride improves the electrical conductivity of the simple Cu 2  O-P 2  O 5  glasses. However, the glasses exhibited a very dark green color. 
     It will be recognized that a combination of two or three halides may be present in the glass compositions. This is evidenced in FIGS. 9, 10, and 11. 
     FIG. 9 sets forth the operable composition area of the system P 2  O 5  -Cu 2  O-F/Cl in weight percent wherein the total F/Cl represents the sum of equal molar amounts of F and Cl. In FIG. 8, points A, B, C, D, E, and F have the following approximate compositions in weight percent: 
     
         A=40% P.sub.2 O.sub.5, 55% Cu.sub.2 O, 5% F/Cl 
    
     
         B=20% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 5% F/Cl 
    
     
         C=15% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 10% F/Cl 
    
     
         D=15% P.sub.2 O.sub.5, 45% Cu.sub.2 O, 40% F/Cl 
    
     
         E=25% P.sub.2 O.sub.5, 35% Cu.sub.2 O, 40% F/Cl 
    
     
         F=40% P.sub.2 O.sub.5, 35% Cu.sub.2 O, 25% F/Cl 
    
     Less than about 15% P 2  O 5  hazards glass instability. The glasses demonstrated colors ranging from light yellow, through amber, to a red amber appearance. The mixture of halide displays a very positive effect in lowering electrical resistivity when compared with any one alone. Thus, resistivities of less than 10 4  ohm cm have been measured at room temperature. 
     FIG. 10 reports the operable composition area of the system P 2  O 5  -Cu 2  O-F/Br in weight percent. In like manner to F/Cl in FIG. 9, the expression F/Br represents the sum of equal molar amounts of F and Br. Points A, B, C, D, E, and F have the following approximate compositions in weight percent: 
     
         A=50% P.sub.2 O.sub.5, 45% Cu.sub.2 O, 5% F/Br 
    
     
         B=20% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 5% F/Br 
    
     
         C=15% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 10% F/Br 
    
     
         D=15% P.sub.2 O.sub.5, 45% Cu.sub.2 O, 40% F/Br 
    
     
         E=40% P.sub.2 O.sub.5, 20% Cu.sub.2 O, 40% F/Br 
    
     
         F=50% P.sub.2 O.sub.5, 20% Cu.sub.2 O, 30% F/Br 
    
     As was the case with the F/Cl compositions, glasses containing less than about 15% P 2  O 5  are unstable with regard to devitrification. Also, the glasses exhibited coloration ranging from light yellow to red amber and electrical resistivities approaching 10 3  ohm cm have been measured at room temperature. 
     FIG. 11 diagrams the operable composition area of the system P 2  O 5  -Cu 2  O-F/I in weight percent. Similarly to F/Cl in FIG. 9 and F/Br in FIG. 10, the term F/I represents the sum of equal molar amounts of F and I. Points A, B, C, D, E, and F have the following approximate compositions in weight percent: 
     
         A=50% P.sub.2 O.sub.5, 45% Cu.sub.2 O, 5% F/I 
    
     
         B=20% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 5% F/I 
    
     
         C=15% P.sub.2 O.sub.5, 75% Cu.sub.2 O, 10% F/I 
    
     
         D=15% P.sub.2 O.sub.5, 40% Cu.sub.2 O, 45% F/I 
    
     
         E=35% P.sub.2 O.sub.5, 20% Cu.sub.2 O, 45% F/I 
    
     
         F=50% P.sub.2 O.sub.5, 20% Cu.sub.2 O, 30% F/I 
    
     Yet again, at least about 15% P 2  O 5  is necessary to provide against glass instability. The glasses were generally somewhat darker than the Cl and Br containing glasses, the colors varying from a light amber to dark brown. Also, the electrical resistivities measured at room temperature were not quite as low as the Cl and Br containing glasses. However, the values were generally less than where only one halide was incorporated into the glass compositions. 
     Furthermore, substitutions in part of copper for silver and vice versa can be made in each of the above groups of compositions outlined in FIGS. 1-11. 
     The electrochromic systems which appear to be of great present interest utilize a solid electrolyte and darken by the electrochemical reduction of an ion to the metal at the cathode or produce a transition metal ion that is colored in the reduced state. Those systems based upon the electrochemical reduction of an ion to the corresponding metal are more efficient because of the large optical absorption coefficient of metals. 
     In order to measure the properties of an electrochromic system, two transparent electrodes were placed on opposite sides of the electrochemical cell. This could be accomplished via R.F. sputtering of Sn-In 2  O 3  or Sb-SnO 2  films. However, a more rapid and convenient system was devised wherein the electrochemical cell was sandwiched between two pieces of glass coated with Sb-SnO 2  films by chemical vapor deposition. This process has been described in such literature as U.S. Pat. Nos. 2,564,707 and 3,331,702. Such a system limits the capability of electrochromic measurements to solid electrolytes having low softening points but that is precisely the type of materials resulting from the present invention. 
     Optical transmission measurements are customarily made with a photodiode using white light. However, the visible spectrum of each system was studied spectrophotometrically. 
     The resistivities reported for solid ionic conductors are normally measured with a.c. current to preclude the occurrence of polarization. For an electrochromic system, however, darkening takes place via an electrochemical reaction, i.e., in the region of polarization. A typical current-voltage relationship existing for an electrochemical reaction is set forth in FIG. 12. 
     In region A of that FIGURE, little current is passed through the cell and no irreversible reactions take place. In region B, electrochemical oxidation and reduction commence. Region C denotes the electrochemical reactions taking place at the maximum rate for the system. Hence, it is in region C where the electrochromic system should be operated for maximum speed. Unfortunately, the current in region C is too great for the Ag 2  O and/or Cu 2  O-halide-P 2  O 5  system, thereby leading to degradation. Consequently, the glasses of the instant invention require operation in region B. 
     By the very nature of the system, i.e., alternating from the discharged to the charged and back to the discharged state of a battery, the resistivity of the cell is voltage dependent. Therefore, the system is best characterized by the current-voltage representation rather than by a single resistivity value. 
     The darkening due to the electrochemical reduction of Ag +  Ag° is fundamentally a very efficient reaction because of the large absorption coefficient of copper and silver. The transmission of an electrochromic system is represented by ##EQU1## where k is the absorption coefficient of the absorbing layer of thickness d at a wavelength λ. 
     Utilizing silver as the example, λ=5600A and k=3.75. In this manner, Equation 1 becomes 
     
         1n(T/T.sub.o)=0.0084d                                      (Equation 2) 
    
     where d is the thickness of silver in A. If the current efficiency of the system is assumed to be 100%, then the transmission can be calculated in terms of the amount of charge passed through the cell. Based upon that assumption, Equation 1 becomes 
     
         1n(T/T.sub.o)=89.6Q                                        (Equation 3) 
    
     where Q is delineated in coulombs. To achieve a transmission of 50%, less than 0.008 coulomb/cm 2  is required. This value corresponds to 8 seconds at a current of 1 ma/cm 2 . FIG. 13 depicts the transmission-time relationship calculated for the silver system at a constant current of 1 ma/cm 2 . Whereas Equations 1-3 were calculated at a wavelength of 5600 A, actual spectra obtained of electrochromic cells of Ag-containing glasses in the darkened state manifest that the transmission is generally uniform across the visible spectrum within about 5%. 
     To reduce the transmission of the Ag-containing system to 50% requires 8.65 μg of Ag/cm 2 . This amount of Ag is equivalent to depleting silver from the glass to a depth of about 235 A. It is conjectured, however, that the Ag comes from a depth of several thousand angstroms within the glass and not just from an interface layer. Even reducing the transmission to 25% demands only about 17 μg of Ag/cm 2 . This quantity of silver is less than 2.4% of that present in a 2 micron film of Ag 2  O·AgCl.·P 2  O 5  glass. The thickness of the typical laminate structure used for measurements is greater than 1000 microns. 
     An electrochemical cell utilizing a cuprous halophosphate glass demonstrates a markedly different mechanism for electrochromic behavior. FIG. 14 illustrates the darkening in transmission exhibited by a glass consisting, by weight, of 40% P 2  O 5 , 20% Cu 2  O, and 40% CuI when a field of one volt is applied thereacross. With this glass the darkening occurs at the anode of the device instead of the cathode, thereby indicating that the electrochemical reaction is the result of an oxidation rather than a reduction mechanism. The color of the darkened film is black, the appearance thereof being similar to that typical of the mixed valency copper oxide black used as optically absorbing coatings. 
     Although the complete details of the mechanism are not known, the summation of the anode reaction is believed to be: 
     
         Cu.sup.+ →Cu.sup.+2 +e.sup.- 
    
     This produces a region of glass at the anode where both cupric and cuprous ions exist, in contrast to the original glass where substantially all the copper is present as cuprous ions. 
     It is well recognized that a strongly allowed optical transition exists between the two valence states of copper leading to the development of copper oxide black, the intensity thereof being proportional to the product of the concentrations of the cupric and cuprous ion species. Consequently, when an electric field of sufficient magnitude is applied to a cuprous halophosphate glass, an optically absorbing film is produced at the anode via a mixed valency mechanism. Measurements on such glasses as that described above, viz., 40% P 2  O 5 , 20% Cu 2  O, and 40% CuI, and 30% P 2  O 5 , 40% Cu 2  O, and 30% CuBr have demonstrated that the darkening mechanism is electrically efficient, requiring on the order of 0.01-0.05 coulombs/cm 2  for significant darkening. FIG. 14 shows a darkening of about 50% after the application of one volt for about four minutes. That glass will fade back to its original transmission by simply removing the applied field. Thus, the glass will assume its original transmission at room temperature without requiring the application of a reverse field thereto. This fading can be expedited by exposure to slightly elevated temperatures. 
     It is believed that this same mechanism of mixed valency darkening is responsible for an additional phenomenon observed in the Cu 2  O-P 2  O 5  -CuX glasses encompassed within the compositions defined in FIGS. 1-3, viz., thermochromic behavior. For example, a glass having a composition of 30% P 2  O 5 , 40% Cu 2  O, and 30% CuBr will change its optical transmission by 50% when it is subjected to a temperature change from 70° C. to 25° C. The glass is more absorbing, i.e., it is darker in color, at the higher temperature. It will be appreciated that under these conditions the oxidation of cuprous ions is effected thermally and occurs throughout the glass rather than solely at an interface, as is the case with the electrochromic mechanism. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-CuCl-P 2  O 5  system. 
     FIG. 2 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-CuBr-P 2  O 5  system. 
     FIG. 3 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-CuI-P 2  O 5  system. 
     FIG. 4 constitutes a ternary composition diagram illustrating an area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-P 2  O 5  -X field, expressed in mole percent, wherein X is at least one halide selected from the group of Cl, Br, and I. 
     FIG. 5 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Ag 2  O-AgCl-P 2  O 5  system. 
     FIG. 6 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Ag 2  O-AgBr-P 2  O 5  system. FIG. 7 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Ag 2  O-AgI-P 2  O 5  system. 
     FIG. 8 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-P 2  O 5  -F system. 
     FIG. 9 constitutes a tenary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-P 2  O 5  -F/C1 system. 
     FIG. 10 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-P 2  O 5  -F/Br system. 
     FIG. 11 constitutes a ternary composition diagram illustrating the area of stable glasses demonstrating an electrical resistivity at 25° C. of less than 10 8  ohm cm produced in the Cu 2  O-P 2  O 5  -F/I system. 
     FIG. 12 sets forth a typical current-voltage relationship existing for an electrochemical reaction. 
     FIG. 13 represents the transmission-time relationship calculated for the silver system at a constant current of 1 ma/cm 2 . 
     FIG. 14 graphically depicts the typical relative transmission: time relationship which a glass having a composition in the P 2  O 5  -Cu 2  O-CuI field exhibits when subjected to a constant applied potential of one volt. The optical transmission is plotted in terms of relative units. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Table I recites several compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses coming within the quadrangle ABCD reported in FIG. 1. Table IA records the batch ingredients utilized, expressed in parts by weight. 
     Melting of the batch ingredients was conducted in covered crucibles, generally VYCOR® brand 96 percent silica crucibles, marketed by Corning Glass Works, Corning, New York, or glazed porcelain, at temperatures between about 70°-1100° C. for about 10-15 minutes. This melting practice, coupled with the character of the batch ingredients, provided a sufficiently reducing environment to insure that the copper was present in the glass in the cuprous state. The time for melting was kept short to avoid loss through volatilization. The molten batches were very fluid, even when cooled to 300°-400° C. The melts were poured onto a steel plate and a part thereof pressed to a thin plate having a thickness of 1 mm or less. 
     Table IB reports visual observations made on the glass specimens and electrical resistivity measurements made at room temperature by contacting the glass with probes from a Simpson 260 volt ohm milliammeter marketed by Simpson Electric Company, Elgin, Ill. 
     
                       TABLE I______________________________________Example No. P.sub.2 O.sub.5                  Cu.sub.2 O CuCl______________________________________1           35         32.5       32.52           30         35         353           40         30         304           40         20         405           40         10         506           40         5          557           40         --         608           35         --         65______________________________________ 
    
     
                       TABLE IA______________________________________Example No.      NH.sub.4 H.sub.2 PO.sub.4                  Cu.sub.2 O CuCl______________________________________1          5.67        3.25       3.252          4.86        3.5        3.53          6.48        3          34          6.48        2          45          6.48        1          56          6.48        0.5        5.67          6.48        --         68          5.67        --         6.5______________________________________ 
    
     
                       TABLE IB______________________________________                        Surface                        ResistanceExample No.      Appearance        (ohms × 10.sup.4)______________________________________1          Clear if quenched, crystal-                        300      line if not2          Clear dark amber glass                        5003          Black glass       10004          Clear amber glass 4005          &#34;                 10006          &#34;                 10007          &#34;                 20008          &#34;                 40______________________________________ 
    
     Table II lists several compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses coming within the quadrangle ABCD reported in FIG. 2. Table IIA reports the batch ingredients used, expressed in parts by weight. 
     Melting of the batch ingredients and forming of the molten batches were undertaken in like manner to the exemplary compositions of Table I. Table IIB recites visual observations noted on the glass samples along with electrical resistivity determinations made at room temperature utilizing a Simpson ohm-meter. 
     
                       TABLE II______________________________________Example No.      P.sub.2 O.sub.5                 Cu.sub.2 O CuBr______________________________________ 9         40         30         3010         40         20         4011         40           17.5       17.512         50         30         2013         40         40         2014         30         --         7015         30         30         4016         30         50         2017         40         --         6018         35         25         4019         45         35         2020         45         30         2521         45         25         3022         45         20         3523         40         15         4524         35         --         65______________________________________ 
    
     
                       TABLE IIA______________________________________Example No.    NH.sub.4 H.sub.2 PO.sub.4               Cu.sub.2 O                        CuBr   H.sub.3 PO.sub.4 (85%)______________________________________ 9       6.48       3        3      --10       --         2        4      6.5211       7.29       1.75     3.75   --12       8.10       3        2      --13       6.48       4        2      --14       4.86       --       215       4.86       3        4      --16       4.86       5        2      --17       6.48       --       6      --18       5.67       2.5      4      --19       7.29       3.5      2      --20       7.29       3        2.5    --21       7.29       2.5      3      --22       7.29       2        3.5    --23       6.48       1.5      4.5    --24       5.67       --       6.5    --______________________________________ 
    
     
                       TABLE IIB______________________________________                        ResistivityExample No.    Appearance          (ohms × 10.sup.4)______________________________________ 9       Clear amber glass   3010       Clear light amber glass                        7011       Clear amber glass   200012       &#34;                   --13       &#34;                   20014       &#34;                   7015       Clear dark amber if quenched,                        10    crystalline if not16       Clear dark amber if quenched,                        500    crystalline if not17       Clear dark amber glass                        20018       Clear light amber glass                        1019       Clear amber glass   100020       &#34;                   50021       &#34;                   40022       &#34;                   100023       &#34;                   10024       &#34;                   70______________________________________ 
    
     Table III records several compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses encompassed within the quadrangle ABCD outlined in FIG. 3. Table IIIA lists the batch ingredients utilized, expressed in parts by weight. 
     Melting of the batch ingredients and forming of the molten batches were conducted in similar fashion to the exemplary compositions of Table I. Table IIIB reports visual observations made on the glass samples along with electrical resistivity measurements determined via a Simpson ohm-meter. 
     
                       TABLE III______________________________________Example No. P.sub.2 O.sub.5                  Cu.sub.2 O CuI______________________________________25          40         30         3026          30         --         7027          40         --         6028          50         --         5029          40          5         5530          40         10         5031          40         15         4532          40         20         40______________________________________ 
    
     
                       TABLE IIIA______________________________________Example No.      NH.sub.4 H.sub.2 PO.sub.4                   Cu.sub.2 O CuI______________________________________25         6.48         3          326         4.86         --         727         6.48         --         628         8.10         --         529         6.48         0.5        5.530         6.48         1          531         6.48         1.5        4.532         6.48         2          4______________________________________ 
    
     
                       TABLE IIIB______________________________________                        ResistivityExample No.     Appearance         (ohms × 10.sup.4)______________________________________25        Clear amber glass  7026        Light amber clear if quenched,                        2     crystalline if not27        Clear amber glass  15028        Dark amber glass   --29        Clear amber glass  30030        &#34;                  5031        Clear light amber glass                        5032        &#34;                  25______________________________________ 
    
     Table IV reports two compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses consisting of more than three components. Table IVA recites the batch constituents employed, expressed in parts by weight. The glasses are stable and exhibit high electrical conductivity. 
     Melting of the batch ingredients and forming of the molten batches were carried out in accordance with the procedure outlined above for the exemplary compositions of Table I. Table IVB notes visual observations made on the glass specimens along with electrical resistivity measurements made with a Simpson ohm-meter. 
     
                       TABLE IV______________________________________Example No.     P.sub.2 O.sub.5              Cu.sub.2 O                        CuO    CuBr______________________________________33        40       15         5     4034        30       15        15     40______________________________________ 
    
     
                       TABLE IVA______________________________________Example No.     Cu.sub.2 O              CuO      CuBr    NH.sub.4 H.sub.2 PO.sub.4______________________________________33        1.5      0.5      4       6.4834        1.5      1.5      4       4.86______________________________________ 
    
     
                       TABLE IVB______________________________________                        ResistivityExample No.     Appearance         (ohms × 10.sup.4)______________________________________33        Clear amber glass  7034        Clear dark amber if quenched,                         5     crystalline if not______________________________________ 
    
     Chemical analyses were performed upon nine of the above glasses to determine the effect of volatilization. The analyses were reported in terms of Cu 2  O, P 2  O 5 , and halide. Table V compares the theoretical compositions as calculated from the batch with the analyzed values. The compositions are adjusted to 100% by weight. 
     
                                           TABLE V__________________________________________________________________________ExampleTheoretical      AnalyzedNo.  P.sub.2 O.sub.5   Cu.sub.2 O       Cl Br  I  P.sub.2 O.sub.5                    Cu.sub.2 O                        Cl Br  I__________________________________________________________________________ 4   38.8   47.4       13.8          --  -- 42.8                    51.7                        5.5                           --  -- 5   38.5   44.5       17.0          --  -- 49.5                    46.1                        4.4                           --  -- 8   33.3   44.8       21.9          --  -- 41.1                    52.8                        6.1                           --  --14   28.7   41.9       -- 29.4              -- 34.7                    42.5                        -- 22.8                               --17   38.5   36.2       -- 25.3              -- 50.7                    38.9                        -- 10.4                               --18   34.1   48.8       -- 17.1              -- 33.5                    47.8                        -- 18.7                               --26   29.2   25.5       -- --  45.3                 35.3                    38.1                        -- --  26.631   39.3   31.3       -- --  29.4                 45.2                    37.1                        -- --  17.732   39.4   34.4       -- --  26.2                 40.1                    38.3                        ----                           21.6__________________________________________________________________________ 
    
     One important finding resulting from the chemical analysis of the copper-containing glasses is that the analyzed concentration of cuprous copper is essentially equivalent to the total copper concentration. The level of Cu o  was too low to analyze but this circumstance does not rule out the presence of colloidal copper in trace amounts to act as a colorant. The primary loss through volatilization was halide with the chloride loss being greater than that of bromide or iodide. 
     Table VI recites the analyzed values of the Examples listed in Table V approximated in terms of mole percent. 
     
                       TABLE VI______________________________________Example No.      P.sub.2 O.sub.5              Cu.sub.2 O                       Cl    Br    I______________________________________ 4         30.4    44.6     19.1  --     -- 5         44.0    40.6     15.6  --    -- 8         35.0    44.3     20.7  --    --14         29.6    36.0     --    34.5  --17         47.2    36.0     --    17.2  --18         29.3    41.7     --    29.2  --26         34.2    36.7     --    --    34.531         44.4    36.7     --    --    19.632         39.2    37.2     --    --    23.6______________________________________ 
    
     Table VII records several compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses having electrical resistivities at room temperature less than about 10 8  ohm cm coming within the quadrangle ABCD cited in FIG. 5. The batch materials consisted of AG 2  O, AgC, and H 3  PO 4  (85% by weight). 
     The melting of the batch constituents and the forming of the resulting melt were undertaken in like manner to the description above with respect to the compositions of Table I. Table VIIA records visual observations noted on the glass specimens and electrical resistivity measurements conducted at room temperature via the probes of a Simpson ohm-meter. 
     
                       TABLE VII______________________________________Example No. P.sub.2 O.sub.5                  Ag.sub.2 O AgCl______________________________________33          34.2       55.8       1034          32.3       52.7       1535          30.4       49.6       2036          26.6       43.4       3037          24.7       40.3       3538          22.8       37.2       4039          25         45         3040          22.5       47.5       3041          20         50         3042          17.5       52.5       3043          15         55         3044          12.5       57.5       3045          25         10         6546          25         53         2247          25         50         2548          15         45         4049          20         40         40______________________________________ 
    
     
                       TABLE VIIA______________________________________                        ResistivityExample No.    Appearance          (ohms × 10.sup.4)______________________________________33       Pale yellow clear if    quenched, crystalline if not                        200034       Pale yellow clear if    quenched, crystalline if not                        100035       Pale yellow clear if    quenched, crystalline if not                        50036       Pale yellow clear glass                        --37       Clear glass if quenched,    crystalline if not38       Clear glass if quenched,    crystalline if not  50039       Clear pale yellow if                        300    quenched, hazy if not40       Clear pale yellow if    quenched, hazy if not                        30041       Clear yellow glass  20042       Clear amber glass   15043       Clear yellow if quenched,                         70    crystalline if not44       Clear yellow if quenched,    crystalline if not  15045       Clear if quenched, hazy                        --    crystalline if not46       Clear if quenched, hazy                        500    if not, yellow47       Clear if quenched, hazy    if not, yellow      50048       Clear if quenched,   40    crystaline if not, yellow49       Clear if quenched,    crystalline if not, yellow                         30______________________________________ 
    
     Table VIII reports several compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses exhibiting electrical resistivities determined at room temperature of less than about 10 8  ohm cm within the quadrangle ABCD represented in FIG. 6. Thebatch materials consisted of Ag 2  O, AgBr, and 85% H 3  PO 4 . 
     The melting of the batch components and the forming of the resulting molten mass were conducted in accordance with the description outlined above with regard to the compositions of Table I. Table VIIIA lists visual observations noted on the glass samples and electrical resistivity measurements made at room temperature utilizing a Simpson ohm-meter. 
     
                       TABLE VIII______________________________________Example No. P.sub.2 O.sub.5                  Ag.sub.2 O AgBr______________________________________50          23         67         1051          20.4       59.6       2052          17.8       52.2       3053          12.8       37.2       5054          17         53         3055          16         54         3056          15         55         3057          14         56         3058          22         68         1059          12         38         5060          11         39         5061          10         40         5062          14         45         4063          20         40         40______________________________________ 
    
     
                       TABLE VIIIA______________________________________                        ResistivityExample No.    Appearance          (ohms × 10.sup.4)______________________________________50       Clear light yellow glass                        50051       Clear yellow glass  20052       &#34;                   10053       &#34;                   1554       &#34;                   7055       Clear yellow is quenched,                        50    crystalline if not56       Clear yellow is quenched,                        50    hazy if not57       Clear yellow if quenched,                        200    crystalline if not58       Clear yellow if quenched,    crystalline if not  50059       Clear brown glass   2060       Clear yellow glass  2061       Clear yellow if quenched,                        20    crystalline if not62       Clear yellow glass  5063       &#34;                   50______________________________________ 
    
     Table IX lists a number of compositions, expressed in weight percent on the oxide basis as calculated from the batch, of stable glasses having electrical resistivities measured at room temperature of less than about 10 8  ohm cm within the area ABCDE represented in FIG. 7. The batch materials consisted of Ag 2  O, AgI, and 85% H 3  PO 4 . 
     The melting of the batch constituents and the forming of the melts were undertaken in the same way as that described above with respect to the compositions of Table I. Table IXA reports the visual appearance observed on the glass specimens and electrical resistivity determinations conducted at room temperature employing a Simpson ohm-meter. 
     
                       TABLE IX______________________________________Example No. P.sub.2 O.sub.5                  Ag.sub.2 O AgI______________________________________64          20         40         4065          15         25         6066          15         35         5067          18         32         5068          26         44         3069          15         55         3070          24         26         5071          14         45         4072          25         35         4073          15         20         6074          10         30         6075          20         20         6076          20         60         2077          10         50         4078          30         20         5079          10         40         5080          35         25         4081          35         35         3082          45         25         30______________________________________ 
    
     
                       TABLE IXA______________________________________                        ResistivityExample No.     Appearance         (ohms × 10.sup.4)______________________________________64        Clear orange glass 1065        Clear yellow glass 0.0266        Clear yellow if quenched,                        0.1     crystalline if not67        Clear light amber glass                        268        Clear yellow glass if quenched,                        70     hazy if not69        Clear amber glass  3070        Clear yellow glass 0.171        Clear yellow glass if quenched,                        0.4     translucent if not72        Clear yellow glass --73        Clear yellow glass if quenched,                        0.01     crystalline if not74        Clear orange glass 0.0775        Clear orange glass if quenched,                        0.02     crystalline if not76        Clear orange glass if quenched,                        150     translucent if not77        Clear yellow glass if quenched,                        0.05     crystalline if not78        Clear dark amber if quenched,                        10     crystalline if not79        Clear orange glass 580        Clear light yellow if quenched,                        10     hazy if not81        Clear yellow glass 20082        Pale yellow glass if quenched,                        200     translucent if not______________________________________ 
    
     Table X records several stable glasses in the Ag 2  O-mixed halide-P 2  O 5  systems where the batches were precipitated in the known manner from aqueous solutions of NaPO 3 , AgNO 3 , NaCl, NaBr, and NaI, dried, and then melted to a glass. The values reported are expressed in weight percent on the oxide basis as calculated from the batch. Table XA recites the batch materials in terms of parts by weight. 
     The melting of the batch ingredients and the forming of the molten batches were carried out in the same fashion as described above with respect to the compositions of Table I. Table XB reports the visual appearance observed and the electrical resistivities measured at room temperature with a Simpson ohm-meter. 
     
                       TABLE X______________________________________Example No.    P.sub.2 O.sub.5            Ag.sub.2 O                     AgCl   AgBr   AgI______________________________________84       30.4    49.6     8.4    --     11.684       12      58       12.6   --     17.485       16      54       12.6   --     17.486       27.6    42.4     --     10     2087       28.5    46.5     15     10     --88       28.5    46.5     15     --     1089       28.5    46.5     15     5      590       26.6    43.4     20     5      5______________________________________ 
    
     
                       TABLE XA______________________________________Example No.    NaPO.sub.3            AgNO.sub.3                     NaCl   NaBr   NaI______________________________________83       21.85   45.60    1.80   --     3.6084       6.96    45.87    2.02   --     4.4585       9.28    42.71    2.02   --     4.4586       4.00    8.57     --     0.55   1.2887       10.88   13.69    0.62   0.55   --88       10.88   13.51    0.62   --     0.6489       10.88   13.60    0.62   0.28   0.3290       10.15   13.46    0.82   0.28   0.32______________________________________ 
    
     
                       TABLE XB______________________________________                     ResistivityExample No.  Appearance   (ohms × 10.sup.4)______________________________________83           Clear glass  --84             &#34;          --85             &#34;          --86           Hazy yellow glass                      10087           Clear if quenched,                     1000        crystalline if not88           Clear if quenched,        crystalline if not                     100089           Clear if quenched,        crystalline if not                     100090           Clear if quenched,        crystaline if not                      500______________________________________ 
    
     Table XI lists several exemplary compositions, expressed in mole percent on the oxide basis as calculated from the batch, wherein various additives were included in the base P 2  O 5  -Ag 2  O-X system, wherein X is selected from the group of Cl, Br, and I. The glasses were prepared in the following manner. Appropriate amounts of AgNO 3  and H 3  PO 4  were blended together and the mixture heated to about 200° C., at which time the AgNO 3  melted and a clear, colorless, homogeneous solution resulted. Upon further heating, viz., up to 500° C., water and nitrogen oxide fumes were evolved. The resultant melt was heated to about 700° C. and held at that temperature for about one hour to insure removal of water and the nitrogen oxides. A AgPO 3  glass was formed by pouring the melt onto a stainless steel block. The glass was annealed at 160° C. 
     An appropriate amount of a silver halide was then mixed with a comminuted sample of th AgPO 3  glass and the mixture fused at about 450° C. The additive materials were then dissolved in the molten mass. To prepare glasses containing BaO, ZnO, La 2  O 3 , desired amounts of the hydrated forms of the nitrates of those oxides were added slowly to the molten Ag 2  O-P 2  O 5  -X. A vigorous reaction ensued with oxides of nitrogen as well as water being emitted. The addition of such constituents as B 2  O 3 , Al 2  O 3 , and LiF can be made by simply incorporating them in that form into the molten Ag 2  O-P 2  O 5  -X. The resultant Ag 2  O-P 2  O 5  -X additive oxide glasses are generally yellow in color. 
     
                       TABLE XI______________________________________Example No.    Ag.sub.2 O             P.sub.2 O.sub.5                      AgCl   Additive Oxide______________________________________92       43.1     43.1     11.0   2.8 La.sub.2 O.sub.393       43.2     43.2     9.6    4.0 Y.sub.2 O.sub.394       40       40       10     10 ZnO95       40.7     40.7     14.3   7.3 BaO96       40.4     40.4     10     9.2 ZnO______________________________________ 
    
     Table XII records electrical resistivity determinations measured at room temperature utilizing a Simpson ohm-meter. Finally, transition temperature determinations via differential thermal analysis, and refractive index measurements are recited. 
     
                       TABLE XII______________________________________     ResistivityExample No.     (ohms)       T.sub.g    n.sub.D______________________________________92        9.3 × 10.sup.5                  --         --93        1.3 × 10.sup.8                  --         --94        1.4 × 10.sup.8                  --         --95        --           178° C.                             1.72596        --           170° C.                             1.720______________________________________ 
    
     Table XIII sets forth a group of compositions, expressed in weight percent on the oxide basis as calulated from the batch, of stable glasses falling within area ABCDEF of FIG. 8 along with a visual description of the glass prepared. Melting of the batch ingredients and forming of the molten batches were carried out in a manner similar to that described above with respect to the working examples of Table I. That is, the batches were compounded, placed into 96 percent silica crucibles, and melted for about 10 minutes at 900° C. The melts were poured onto a steel slab and quenched under the pressure of a graphite block into a thin plate of about 1 mm thickness. The batch materials employed were NH 4  H 2  PO 4 , CuF 2 , and NH 4  F.HF. 
     Table XIIIA reports the compositions as calculated in terms of mole percent and also includes electrical resistivity measurements (ohm cm) conducted at room temperature (˜25° C.) at 120 Hz, 1 KHz, and 10 KHz utilizing painted silver electrodes. 
     
                       TABLE XIII______________________________________Example No.    Cu.sub.2 O            P.sub.2 O.sub.5                   F     Visual Appearance______________________________________97       12      77     11    Dark glass98       16      37     47    Dark glass99        5      90      5    Dark, sticky glass100       7      83     10    Dark, sticky glass101       6      77     17    Dark, sticky glass102      18      76      6    Dark glass103      53      39      8    Dark, partly devi-                         trified glass______________________________________ 
    
     
                       TABLE XIIIA______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                  F    120Hz  1KHz   10KHz______________________________________97     7       45      48   7 × 10.sup.7                              6.8 × 10.sup.7                                     5.8 × 10.sup.798     4       9       87   --     --     2.6 × 10.sup.799     4       68      28   6.6 × 10.sup.5                              6.3 × 10.sup.5                                     6.1 × 10.sup.5100    4       50      46   1.9 × 10.sup.6                              1.9 × 10.sup.6                                     6.5 × 10.sup.5101    3       37      60   1.3 × 10.sup.7                              1.3 × 10.sup.7                                     1.1 × 10.sup.7102    13      56      31   --     --     4.9 × 10.sup.7103    34      25      41   --     --     5.8 × 10.sup.7______________________________________ 
    
     Table XIV lists a number of compositions, reported in terms of weight percent on the oxide basis as calculated from the batch, of relatively stable glasses encompassed within the area ABCDEF of FIG. 9 accompanied with a visual description of each glass prepared. The melting of the batch ingredients and the forming of the resultant melt were undertaken in like manner to that described immediately above with regard to Table XIII. The batch ingredients included NH 4  H 2  PO 4 , CuF, CuCl, and NH 4  F.HF. The quantities of the batch components were adjusted such that equal molar amounts of fluoride and chloride were present in the batch. 
     Table XIVA recites the compositions as calculated in terms of mole percent and lists electrical resistivity determinations (reported in ohm cm) measured at room temperature (˜25° C.) at 120 Hz, 1 KHz, and 10 KHz utilizing painted silver electrodes. 
     
                       TABLE XIV______________________________________Example No.    Cu.sub.2 O            P.sub.2 O.sub.5                    F    Cl   Visual Appearance______________________________________104      55      34      3.8  7.2  Light amber glass105      62      19      6.5  12.5 Dark, partly                              devitrified glass106      41      25      11.5 21.5 Yellow glass107      74      18      2.8  5.2  Dark surface                              devitrified glass108      51      34      5.2  9.8  Amber, partly                              devitrified glass109      56      19      8.7  16.3 Dark glass______________________________________ 
    
     
                       TABLE XIVA______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                 F   Cl  120Hz  1KHz   10KHz______________________________________104    37      23     20  20  3.7 × 10.sup.5                                1.8 × 10.sup.5                                       4.4 × 10.sup.4105    36      8      28  28  2.0 × 10.sup.3                                1.9 × 10.sup.3                                       1.1 × 10.sup.3106    17      11     36  36  3.4 × 10.sup.3                                3.4 × 10.sup.3                                       2.7 × 10.sup.3107    54      14     16  16  8.6 × 10.sup.4                                8.1 × 10.sup.4                                       7.7 ×10.sup.4108    31      21     24  24  3.9 × 10.sup.4                                3.2 × 10.sup.4                                       1.1 × 10.sup.4109    27      9      32  32  4.4 × 10.sup.4                                4 × 10.sup.4                                       4 × 10.sup.4______________________________________ 
    
     Table XV records exemplary glasses, stated in terms of weight percent on the oxide basis as calculated from the batch, of relatively stable glasses having compositions within the area ABCDEF of FIG. 10 and includes a visual description of each glass prepared. The melting of the batch materials and the forming of the molten batch into thin sheet were conducted in accordance with the method described with reference to Table XIII. NH 4  H 2  PO 4 , CuF 2 , CuBr, and NH 4  F.HF comprised bath ingredients therefor. The quantities of chloride and fluoride were carefully controlled such that equal molar amounts of each were present in the batch. 
     Table XVA lists the glasses as calculated in terms of mole percent and also reports electrical resistivity data (expressed as ohm cm) measured at room temperature (˜25° C.) at 120Hz, 1KHz, and 10KHz utilizing painted silver electrodes. 
     
                       TABLE XV______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                  F    Br   Visual Appearance______________________________________110    46      34      3.8  16.2 Yellow, sticky glass111    47      19      6.3  27.7 Amber glass112    24      46      5.4  24.6 Amber glass113    36      28      6.9  20.1 Yellow-green glass114    17      58      4.8  20.2 Dark glass115    74      18      1.5  6.5  Dark glass116    51      34      3    12   Yellow, amber                            sticky glass117    56      19      5    20   Red, amber glass118    31      48      4    17   Amber glass______________________________________ 
    
     
                       TABLE XVA______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                 F   Br  120Hz  1KHz   10KHz______________________________________110    33      25     21  21  1.9 × 10.sup.4                                1.5 × 10.sup.4                                       9.5 × 10.sup.3111    29      11     30  30  1.3 × 10.sup.3                                2.6 × 10.sup.3                                       3.5 × 10.sup.3112    16      32     26  26  3.1 × 10.sup.7                                2.7 × 10.sup.7                                       1.6 × 10.sup.7113    21      17     31  31  4.9 × 10.sup.3                                2.5 × 10.sup.3                                       1.2 × 10.sup.3114    12      40     24  24  --     --     1.4 × 10.sup.7115    64      16     10  10  4.1 × 10.sup.5                                4.1 × 10.sup.5                                       4.0 × 10.sup.5116    40      27     17  17  6 × 10.sup.4                                3.6 × 10.sup.4                                       2.7 × 10.sup.4117    40      14     23  23  2.2 × 10.sup.3                                2.0 × 10.sup.3                                       1.7 × 10.sup.3118    17      37     23  23  1.0 ×  10.sup.7                                9.8 × 10.sup.6                                       7.7 × 10.sup.6______________________________________ 
    
     Table XVI lists a number of working examples, recorded in terms of weight percent on the oxide basis as calculated from the batch, of relatively stable glasses having compositions included within the area ABCDEF of FIG. 11 along with a visual description of each glass body. The melting of the batch materials and the pressing of the melt into thin sheet were carried out in a manner similar to that described above with respect to Table XIII. The batch ingredients for the glasses included NH 4  H 2  PO 4 , CuF 2 , CuI, and NH 4  F.HF. The contents of fluoride and iodide were so controlled as to incorporate equal molar amounts of each into the batch. 
     Table XVIA recites the glasses as calculated in terms of mole percent and also tabulates electrical resistivity determinations (reported in ohm cm) measured at room temperature (˜25° C.) at 120Hz, 1KHz, and 10KHz employing painted silver electrodes. 
     
                       TABLE XVI______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                  F   I    Visual Appearance______________________________________119    74      18      1   7    Dark glass120    51      34      2   13   Red-brown, partly                           devitrified glass121    56      19      3.2 21.8 Dark amber glass122    31      47      2.7 19.3 Light amber glass123    26      32      5.4 36.6 Amber, surface                           devitrified glass124    13      76      1.5 9.5  Dark brown glass______________________________________ 
    
     
                       TABLE XVIA______________________________________ExampleNo.    Cu.sub.2 O          P.sub.2 O.sub.5                 F   I   120Hz  1KHz   10KHz______________________________________119    69      17      7   7  9.8 × 10.sup.5                                9.2 × 10.sup.5                                       8.6 × 10.sup.5120    45      29     13  13  3.0 × 10.sup.5                                1.7 × 10.sup.5                                       9.0 × 10.sup.4121    45      15     20  20  2.4 × 10.sup.4                                2.2 × 10.sup.4                                       2.0 × 10.sup.4122    26      40     17  17  2.6 × 10.sup.5                                2.1 × 10.sup.5                                       1.7 × 10.sup.5123    18      24     29  29  2.2 × 10.sup.6                                1.3 × 10.sup.6                                       1 × 10.sup.6124    12      68     10  10  --     --     1.4 × 10.sup.7______________________________________ 
    
     Table XVII reports several other glasses, expressed in weight percent on the oxide basis as calculated from the batch, having compositions within the base P 2  O 5  -Ag 2  O-X system, wherein X is selected from the group of Cl, Br, I, and equal molar amounts of Cl and I. The glasses were prepared in like manner to that described above with respect to the examples listed in Table XI except that no additive oxides were incorporated therein. Table XVII also records d.c. electrical resistivity measurements conducted at room temperature (˜25° C.) utilizing the three probe method. 
     
                       TABLE XVII______________________________________                                  ResistivityExample                                (ohm cm ×No.    Ag.sub.2 O          P.sub.2 O.sub.5                 AgCl  AgBr  AgI  10.sup.4______________________________________125    59.7    36.5   3.8   --    --   173126    57.2    35.1    7.7  --    --   73127    54.8    33.5   11.7  --    --   49128    52.1    31.9   16.0  --    --   26129    46.5    28.5   25.0  --    --   8.6130    41.1    25.2   33.7  --    --   3.2131    58.9    26.1   --     5.0  --   152132    52.7    32.3   --    15.0  --   41133    37.1    22.8   --    40.1  --   2.7134    57.9    35.8   --    --     6.3 81135    50.9    31.1   --    --    18.0 27136    23.1    15.2   --    25.0  2.7137    41.2    25.3   12.7  --    20.8 2.2138    44.2    27.2   10.8  --    17.8 8.6139    51.6    31.6    6.4  10.4  29.8______________________________________