ALKALI-FREE GLASS

Abstract

An alkali-free glass includes, in mol % in terms of oxides: SiO.sub.2: 63-75%; Al.sub.2O.sub.3: 10-16%; B.sub.2O.sub.3: 0-5%; MgO: 0.1-15%; CaO: 0.1-12%; SrO: 0-8%; and BaO: 0-6%. [MgO]/[CaO] is 1.5 or smaller. A value of Formula (A) is 82.5 or larger. A value of Formula (B) is 690 or larger and 800 or smaller. A value of Formula (C) is 100 or smaller. A value of Formula (D) is 20 or smaller. The alkali-free glass has a Young's modulus of 83 GPa or larger and a surface devitrification viscosity η.sub.c of 10.sup.4.2 dPa.Math.s or higher.

Claims

1. An alkali-free glass, comprising, in mol % in terms of oxides: SiO.sub.2: 63-75%; Al.sub.2O.sub.3: 10-16%; B.sub.2O.sub.3: 0-5%; MgO: 0.1-15%; CaO: 0.1-12%; SrO: 0-8%; and BaO: 0-6%, wherein: [MgO]/[CaO] is 1.5 or smaller; a value of Formula (A) is 82.5 or larger, Formula (A) being 1.131[SiO.sub.2]+1.933 [Al.sub.2O.sub.3]+0.362[B.sub.2O.sub.3]+2.049[MgO]+1.751[CaO]+1.471[SrO]+1.039[BaO]−48.25; a value of Formula (B) is 690 or larger and 800 or smaller, Formula (B) being 35.59[SiO.sub.2]+37.34[Al.sub.2O.sub.3]+24.59[B.sub.2O.sub.3]+31.13[MgO]+31.26[CaO]+30.78[SrO]+31.98[BaO]−2761; a value of Formula (C) is 100 or smaller, Formula (C) being −9.01[SiO.sub.2]+36.36[Al.sub.2O.sub.3]+5.7[B.sub.2O.sub.3]+5.13[MgO]+17.25[CaO]+7.65[SrO]+10.58[BaO]; a value of Formula (D) is 20 or smaller, Formula (D) being {−0.731[SiO.sub.2]+1.461[Al.sub.2O.sub.3]−0.157[B.sub.2O.sub.3]+1.904[MgO]+3.36[CaO]+3.411[SrO]+1.723[BaO]+(−3.318[MgO][CaO]−1.675[MgO][SrO]+1.757[MgO][BaO]+4.72[CaO][SrO]+2.094[CaO][BaO]+1.086[SrO][BaO])}/([MgO]+[CaO]+[SrO]+[BaO]); and the alkali-free glass has a Young's modulus of 83 GPa or larger and a surface devitrification viscosity η.sub.c of 10.sup.4.2 dPa.Math.s or higher.

2. The alkali-free glass according to claim 1, wherein a value of Formula (E) is in a range of 1.50 to 5.50, Formula (E) being 4.379[SiO.sub.2]+5.043[Al.sub.2O.sub.3]+4.805[B.sub.2O.sub.3]+4.828[MgO]+4.968[CaO]+5.051[SrO]+5.159[BaO]−453.

3. The alkali-free glass according to claim 1, having a strain point of 690° C. or higher.

4. The alkali-free glass according to claim 1, having a density of 2.8 g/cm.sup.3 or lower and an average thermal expansion coefficient in 50-350° C. of 30×10.sup.−7/° C. to 45×10.sup.−7/° C.

5. The alkali-free glass according to claim 1, having a temperature T.sub.2 at which a glass viscosity becomes 10.sup.2 dPa.Math.s of 1800° C. or lower and a temperature T.sub.4 at which the glass viscosity becomes 10.sup.4 dPa.Math.s of 1400° C. or lower.

6. The alkali-free glass according to claim 1, having an internal devitrification temperature of 1320° C. or lower.

7. The alkali-free glass according to claim 1, having an internal devitrification viscosity η.sub.d of 10.sup.4.4 dPa.Math.s or higher.

8. The alkali-free glass according to claim 1, having a crystal growth rate of 100 μm/hr or lower.

9. The alkali-free glass according to claim 1, comprising at least one selected from the group consisting of Li.sub.2O, Na.sub.2O, and K.sub.2O in an amount of 0.2% or smaller in total in mole % in terms of oxides.

10. An alkali-free glass, comprising, in mol % in terms of oxides: SiO.sub.2: 50-80%; Al.sub.2O.sub.3: 8-20%; Li.sub.2O+Na.sub.2O+K.sub.2O: 0-0.2%, and P.sub.2O.sub.5: 0-1%, wherein [MgO]/[CaO] is 1.5 or smaller, and the alkali-free glass has: a Young's modulus of 83 GPa or larger; a strain point of 690° C. or higher; a temperature T.sub.4 at which a glass viscosity becomes 10.sup.4 dPa.Math.s of 1400° C. or lower; a temperature T.sub.2 at which the glass viscosity becomes 10.sup.2 dPa.Math.s of 1800° C. or lower; an internal devitrification temperature of 1320° C. or lower; an internal devitrification viscosity η.sub.d of 10.sup.4.4 dPa.Math.s or higher; a surface devitrification viscosity η.sub.c of 10.sup.4.2 dPa.Math.s or higher; a crystal growth rate of 100 μm/hr or lower; a density of 2.8 g/cm.sup.3 or lower; and an average thermal expansion coefficient in 50-350° C. of 30×10.sup.−7 to 45×10.sup.−7/° C.

11. The alkali-free glass according to claim 10, comprising B.sub.2O.sub.3 in an amount of 0-5% in mol % in terms of oxides.

12. The alkali-free glass according to claim 10, comprising, in mol % in terms of oxides: MgO: 0.1-15%; CaO: 0.1-12%; SrO: 0-8%; and BaO: 0-6%.

13. The alkali-free glass according to claim 10, comprising, in mol % in terms of oxides: B.sub.2O.sub.3: 0-5%; MgO: 0.1-15%; CaO: 0.1-12%; SrO: 0-8%; and BaO: 0-6%.

14. The alkali-free glass according to claim 10, wherein a value of Formula (A) is 82.5 or larger, Formula (A) being 1.131[SiO.sub.2]+1.933[Al.sub.2O.sub.3]+0.362[B.sub.2O.sub.3]+2.049[MgO]+1.751[CaO]+1.471[SrO]+1.039[BaO]−48.25.

15. The alkali-free glass according to claim 10, wherein a value of Formula (B) is 690 or larger and 800 or smaller, Formula (B) being 35.59[SiO.sub.2]+37.34[Al.sub.2O.sub.3]+24.59[B.sub.2O.sub.3]+31.13 [MgO]+31.26[CaO]+30.78[SrO]+31.98[BaO]−2761.

16. The alkali-free glass according to claim 10, wherein a value of Formula (C) is 100 or smaller, Formula (C) being −9.01[SiO.sub.2]+36.36[Al.sub.2O.sub.3]+5.7[B.sub.2O.sub.3]+5.13[MgO]+17.25[CaO]+7.65[SrO]+10.58[BaO].

17. The alkali-free glass according to claim 10, wherein a value of Formula (D) is 20 or smaller, Formula (D) being {−0.731[SiO.sub.2]+1.461[Al.sub.2O.sub.3]−0.157[B.sub.2O.sub.3]+1.904[MgO]+3.36[CaO]+3.411[ SrO]+1.723[BaO]+(−3.318[MgO][CaO]−1.675[MgO][SrO]+1.757[MgO][BaO]+4.72[CaO][SrO]+2.094[CaO][BaO]+1.086[SrO][BaO])}/([MgO]+[CaO]+[SrO]+[BaO]).

18. The alkali-free glass according to claim 10, wherein a value of Formula (E) is 1.50-5.50, Formula (E) being 4.379[SiO.sub.2]+5.043[Al.sub.2O.sub.3]+4.805[B.sub.2O.sub.3]+4.828[MgO]+4.968[CaO]+5.051 [ SrO]+5.159[BaO]−453.

19. The alkali-free glass according to claim 1, comprising F in an amount of 1.5 mol % or smaller.

20. The alkali-free glass according to claim 1, comprising SnO.sub.2 in an amount of 0.5% or smaller in mol % in terms of oxides.

21. The alkali-free glass according to claim 1, comprising ZrO.sub.2 in an amount of 0.09% or smaller in mol % in terms of oxides.

22. The alkali-free glass according to claim 1, wherein a glass β-OH value is 0.01 mm-1 or larger and 0.5 mm.sup.−1 or smaller.

23. The alkali-free glass according to claim 1, having an annealing point of 850° C. or lower.

24. The alkali-free glass according to claim 1, wherein a compaction is 150 ppm or smaller when being held at 600° C. for 80 min.

25. The alkali-free glass according to claim 1, having an equivalent cooling rate of 5° C./min or higher and 800° C./min or lower.

26. The alkali-free glass according to claim 1, wherein a sludge volume when the glass is subjected to an etching process is 30 ml or smaller.

27. The alkali-free glass according to claim 1, having a photoelastic constant of 31 nm/MPa/cm or smaller.

28. A glass plate comprising the alkali-free glass according to claim 1, having a length of at least one side of 2400 mm or longer and a thickness of 1.0 mm or smaller.

29. The glass plate according to claim 28, manufactured by a float process or a fusion process.

30. A display panel, comprising the alkali-free glass according to claim 1.

31. A semiconductor device, comprising the alkali-free glass according to claim 1.

32. An information recording medium, comprising the alkali-free glass according to claim 1.

33. A planar antenna, comprising the alkali-free glass according to claim 1.

34. A dimming laminate, comprising the alkali-free glass according to claim 1.

35. A vehicular window glass, comprising the alkali-free glass according to claim 1.

36. An acoustic vibration plate, comprising the alkali-free glass according to claim 1.

37. The alkali-free glass according to claim 10, comprising F in an amount of 1.5 mol % or smaller.

38. The alkali-free glass according to claim 10, comprising SnO.sub.2 in an amount of 0.5% or smaller in mol % in terms of oxides.

39. The alkali-free glass according to claim 10, comprising ZrO.sub.2 in an amount of 0.09% or smaller in mol % in terms of oxides.

40. The alkali-free glass according to claim 10, wherein a glass β-OH value is 0.01 mm.sup.−1 or larger and 0.5 mm.sup.−1 or smaller.

41. The alkali-free glass according to claim 10, having an annealing point of 850° C. or lower.

42. The alkali-free glass according to claim 10, wherein a compaction is 150 ppm or smaller when being held at 600° C. for 80 min.

43. The alkali-free glass according to claim 10, having an equivalent cooling rate of 5° C./min or higher and 800° C./min or lower.

44. The alkali-free glass according to claim 10, wherein a sludge volume when the glass is subjected to an etching process is 30 ml or smaller.

45. The alkali-free glass according to claim 10, having a photoelastic constant of 31 nm/MPa/cm or smaller.

46. A glass plate comprising the alkali-free glass according to claim 10, having a length of at least one side of 2400 mm or longer and a thickness of 1.0 mm or smaller.

47. The glass plate according to claim 46, manufactured by a float process or a fusion process.

48. A display panel, comprising the alkali-free glass according to claim 10.

49. A semiconductor device, comprising the alkali-free glass according to claim 10.

50. An information recording medium, comprising the alkali-free glass according to claim 10.

51. A planar antenna, comprising the alkali-free glass according to claim 10.

52. A dimming laminate, comprising the alkali-free glass according to claim 10.

53. A vehicular window glass, comprising the alkali-free glass according to claim 10.

54. An acoustic vibration plate, comprising the alkali-free glass according to claim 10.

Description

EXAMPLES

[0195] Although Examples will be described below, the invention is not limited to those Examples. In the following, Examples 1-12 and Examples 17-24 are Inventive Examples and Examples 13-16 are Comparative Examples.

[0196] Raw materials of respective components were mixed so as to obtain a target glass composition (unit: mol %) of each of Examples 1-24 and melted at 1600° C. for one hour using a platinum crucible. After the melting, a molten liquid was caused to flow out onto a carbon plate, held at a temperature that is a glass transition point+30° C. for 60 minutes, and cooled to room temperature (25° C.) at a rate of 1° C. per minute thereby obtaining plate-like glass. A glass plate was obtained by mirror-polishing the plate-like glass and subjected to various evaluations. Results are shown in Tables 1-3. In Tables 1-3, each value shown in parentheses is a calculated value or an estimated value. In Tables 1-3, “RO” means a total content of alkali earth metal oxides.

[0197] Measurement methods of respective physical properties will be described below.

(Average Thermal Expansion Coefficient)

[0198] A measurement was carried out using a differential thermal dilatometer (TMA) according to a method that is prescribed in JIS R3102 (year 1995). The measurement temperature range was room temperature to 400° C. or higher and an average thermal expansion coefficient in a temperature range 50-350° C. is shown in the unit (×10.sup.−7)/° C.

(Density)

[0199] A measurement was performed on a lump of glass in an amount of about 20 g not containing bubbles by a liquid weighing method according to a method that is prescribed in JIS Z 8807 (year 2012).

(Strain Point)

[0200] A measurement was carried out by a fiber elongation method according to a method that is prescribed in JIS R3103-2 (year 2001).

(Annealing Point)

[0201] A measurement was carried out by a fiber elongation method according to a method that is prescribed in JIS R3103-2 (year 2001).

(Glass Transition Point)

[0202] A measurement was carried out by a thermal expansion method according to a method that is prescribed in JIS R3103-3 (year 2001).

(Young's Modulus)

[0203] A measurement was performed on glass that was 1.0-10 mm in thickness by an ultrasonic pulse method according to a method that is prescribed in JIS R 1602 (year 1995).

(T.SUB.2.)

[0204] Viscosity was measured using a rotary viscometer and a temperature at which the viscosity becomes 10.sup.2 dPa.Math.s was measured according to a method that is prescribed in ASTM C 965-96 (year 2017).

(T.SUB.4.)

[0205] Viscosity was measured using a rotary viscometer and a temperature at which the viscosity becomes 10.sup.4 dPa.Math.s was measured according to a method that is prescribed in ASTM C 965-96 (year 2017).

(Surface Devitrification Temperature T.SUB.c.)

[0206] Glass was pulverized and classification was performed using a test sieve so as to obtain particles in a diameter range of 2-4 mm. The glass cullet thus obtained was subjected to ultrasonic cleaning in isopropyl alcohol for five minutes, cleaned using ion exchanged water, dried, put into a platinum dish, and then subjected to heat treatment for 17 hours in an electric furnace that was controlled at a constant temperature. Heat treatment temperatures were set at intervals of 10° C.

[0207] After the heat treatment, the glass was removed from the platinum dish and a maximum temperature at which crystals were deposited in the glass surface and a minimum temperature at which no crystals were deposited were determined through observation using an optical microscope.

[0208] Each of a maximum temperature at which crystals were deposited in the glass surface and a minimum temperature at which no crystals were deposited was measured once. In the case where it was difficult to judge whether crystals were deposited, measurement was possibly done two times.

[0209] An average value of the measured maximum temperature at which crystals were deposited in the glass surface and the measured minimum temperature at which no crystals were deposited was determined as a glass surface devitrification temperature T.sub.c.

(Surface Devitrification Viscosity η.SUB.c.)

[0210] A glass surface devitrification temperature T.sub.c was determined by the above method and glass surface devitrification viscosity η.sub.c was determined by measuring glass viscosity at the glass surface devitrification temperature T.sub.c.

(Internal Devitrification Temperature T.SUB.d.)

[0211] Glass was pulverized and classification was performed using a test sieve so as to obtain particles in a diameter range of 2-4 mm. The glass cullet thus obtained was subjected to ultrasonic cleaning in isopropyl alcohol for five minutes, cleaned using ion exchanged water, dried, put into a platinum dish, and then subjected to heat treatment for 17 hours in an electric furnace that was controlled at a constant temperature. Heat treatment temperatures were set at intervals of 10° C.

[0212] After the heat treatment, the glass was removed from the platinum dish and a maximum temperature at which crystals were deposited in the glass surface and a minimum temperature at which no crystals were deposited were determined through observation using an optical microscope.

[0213] Each of a maximum temperature at which crystals were deposited inside the glass and a minimum temperature at which no crystals were deposited was measured once. In the case where it was difficult to judge whether crystals were deposited, measurement was possibly done two times.

[0214] An average value of the measured maximum temperature at which crystals were deposited inside the glass and the measured minimum temperature at which no crystals were deposited was determined as a glass internal devitrification temperature T.sub.d.

(Internal devitrification viscosity η.sub.d)

[0215] A glass internal devitrification temperature T.sub.d was determined by the above method and glass internal devitrification viscosity η.sub.d was determined by measuring glass viscosity at the glass internal devitrification temperature T.sub.d.

(Crystal Growth Rate)

[0216] Pulverized glass particles are put into a platinum dish and heat-treated for 17 hours in an electric furnace that is controlled around a surface devitrification temperature, thereby producing plural primary crystal samples in which minute primary crystals are deposited in the glass surface. The produced primary crystal samples are held for 1-4 hours at temperatures having intervals 20° C. in such a temperature range that the glass viscosity is 10.sup.4-10.sup.6 dPa.Math.s, thereby growing crystals at the respective holding temperatures. Lengths of longest portions of crystal grains obtained before and after the holding at each holding temperature were measured, a difference between the crystal sizes obtained before and after the holding at each holding temperature was determined, and a crystal growth rate at each holding temperature was determined by dividing the crystal size difference by the holding time. A maximum value of the growth rates in such a temperature range that the glass viscosity became 10.sup.4-10.sup.6 dPa.Math.s was employed as a crystal growth rate.

(Etching Rate)

[0217] Raw materials of respective components were mixed so as to obtain each of target glass compositions shown in Tables 1-3, melted in an electric furnace, and clarified, thereby obtaining each alkali-free glass base material. Each alkali-free glass base material was mirror-polished, cut into an alkali-free glass substrate 1 of 20 mm×30 mm×0.5 mm (thickness), cleaned, dried, and subjected to a mass measurement.

[0218] An aqueous solution (liquid chemical) adjusted so as to contain 5 mass % hydrofluoric acid and 2 mass % hydrochloric acid was put into a container made of Teflon (registered trademark) and held at 40° C. using a constant temperature bath. The entire alkali-free glass substrate was immersed in the liquid chemical for 20 minutes. The immersed alkali-free glass substrate was cleaned by pure water and dried, and then subjected to a mass measurement.

[0219] A surface area was calculated from the sample dimensions and an etching rate per unit time was calculated by dividing, by the surface area, a quotient obtained by dividing a mass reduction by a density and then dividing a resulting quotient by the immersion time.

(Sludge Volume)

[0220] The entire alkali-free glass substrate 1 that was used for calculating an etching rate was again immersed in the liquid chemical of 40° C. and melted completely. After 1.8 ml of 50 mass % hydrofluoric acid was added to the above liquid chemical to compensate for hydrofluoric acid consumed by the etching, a new alkali-free glass substrate 2 of 20 mm×30 mm×0.5 mm (thickness) was immersed in the liquid chemical and also melted completely. Furthermore, after 1.8 ml of 50 mass % hydrofluoric acid was added to the above liquid chemical, a new alkali-free glass substrate 3 of 20 mm×30 mm×0.5 mm (thickness) was immersed in the liquid chemical and melted completely according to the same procedure. The liquid chemical in which the alkali-free glass substrate 3 had been melted was held for one day and night (24 hours) while being stirred by a magnetic stirrer, thereby producing sludge (insoluble matter) in the liquid chemical. To prevent evaporation of the liquid chemical, a lid made of Teflon (registered trademark) was put on the container during the test. Subsequently, the liquid chemical and sludge contained in the container made of Teflon (registered trademark) were transferred to a graduated cylinder and held for 24 hours to precipitate sludge. A volume of the sludge was measured using the scale of the graduated cylinder and employed as a sludge volume.

TABLE-US-00001 TABLE 1 mol % Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 SiO.sub.2 69.0 65.1 67.5 70.2 71.3 68.8 67.3 69.3 Al.sub.2O.sub.3 14.0 12.4 14.1 12.7 10.9 15.2 14.1 11.5 B.sub.2O.sub.3 0 4.3 1.5 0.3 0.3 0.5 1.3 0.6 MgO 7.0 9.1 5.9 6.3 5.3 4.6 6.3 5.6 CaO 5.0 7.2 5.9 6.5 10.3 3.5 5.7 8.9 SrO 0.0 0.7 4.0 0.9 0.3 5.6 1.2 2.8 BaO 5.0 1.2 1.1 3.1 1.6 1.8 4.1 1.3 RO 17.0 18.2 16.9 16.8 17.5 15.5 17.3 18.6 MgO/CaO 1.40 1.26 1.00 0.97 0.51 1.31 1.11 0.63 Value of formula (A) 85.1 84.4 85.3 84.6 84.6 84.8 84.5 85.1 Value of formula (B) 752 693 731 744 738 750 735 730 Value of formula (C) 62.4 77.8 87.3 14.9 −20.5 81.5 96.9 14.6 Value of formula (D) 8.62 6.70 16.80 7.17 5.43 16.79 13.51 16.63 Value of formula (E) 4.18 4.70 4.57 3.00 2.02 4.50 5.01 3.44 Average thermal expansion 38.0 37.3 38.5 38.1 38.9 38.6 40.4 43.3 coefficient (×10.sup.−7 / ° C.) Density (g/cm.sup.3) 2.65 2.53 2.59 2.60 2.54 2.64 2.64 2.59 Strain point (° C.) 738 692 723 733 723 750 721 710 Annealing point (° C.) 798 745 782 792 781 810 780 767 Glass transition point (° C.) 791 747 778 788 777 802 777 765 Young's modulus (GPa) 85.7 84.8 85.8 85.4 85.2 85.5 (83) 83.3 T.sub.2 (° C.) 1729 1635 1693 1756 1762 1737 1706 1712 T.sub.4 (° C.) 1358 1273 1331 1365 1361 1368 1335 1330 Surface devitrification temp. T.sub.c (° C.) 1285 1215 1295 1255 1295 1345 1245 1275 Internal devitrification temp. T.sub.d (° C.) 1235 1175 1235 1235 1295 1295 1195 1245 Surface devitrification viscosity η.sub.c   10.sup.4.6   10.sup.4.5   10.sup.4.3   10.sup.4.9   10.sup.4.5   10.sup.4.2   10.sup.4.3   10.sup.4.4 (dPa .Math. s) Internal devitrification viscosity η.sub.d   10.sup.5.1   10.sup.4.9   10.sup.4.8   10.sup.5.1   10.sup.4.5   10.sup.4.6   10.sup.5.2   10.sup.4.7 (dPa .Math. s) Crystal growth rate (μm/hr) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) Sludge volume (ml) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) Etching rate (μm/min) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) Photoelastic constant (nm/MPa/cm) (26.2) (28.3) (27.1) (27.0) (27.6) (26.7) (26.5) (27.1) Specific modulus (MN .Math. m/kg) 32.3 33.5 33.1 32.9 33.5 32.4 −31.4 32.2 Equivalent cooling rate (° C./min) 40 40 40 40 40 40 40 40 Compaction (ppm) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100)

TABLE-US-00002 TABLE 2 mol % Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ex. 15 Ex. 16 SiO.sub.2 69.0 69.7 70.3 68.2 67.9 66.0 65.7 67.0 Al.sub.2O.sub.3 13.5 12.3 11.8 12.4 12.3 11.3 14.3 13.8 B.sub.2O.sub.3 1.3 0.8 0.2 1.0 4.5 4.5 0.5 1.0 MgO 7.5 6.8 6.8 7.5 5.2 8.2 8.8 4.2 CaO 5.7 6.3 4.8 5.3 5.1 7.0 6.2 6.6 SrO 0.6 2.3 3.1 2.1 3.6 3.0 3.5 6.6 BaO 2.4 1.8 3 3.5 1.4 0 1.0 0.8 RO 16.2 17.2 17.7 18.4 15.2 18.2 19.5 18.2 MgO/CaO 1.32 1.08 1.42 1.42 1.02 1.17 1.42 0.64 Value of formula (A) 85.1 84.9 84.2 84.6 80.2 83.3 89.0 85.3 Value of formula (B) 738 736 740 730 699 687 731 729 Value of formula (C) 43.4 4.0 −30.1 25.1 18.7 27.6 120.3 98.1 Value of formula (D) 4.29 9.04 10.79 12.69 9.20 9.64 19.01 30.03 Value of formula (E) 3.42 3.12 3.12 4.19 3.27 4.14 5.34 5.32 Average thermal expansion (36.3) (38.6) (40.1) (40.6) (35.4) 38.6 (40.6) (43.1) coefficient (×10.sup.−7 / ° C.) Density (g/cm.sup.3) (2.57) (2.58) (2.63) (2.64) 2.55 2.52 (2.61) (2.64) Strain point (° C.) (735) (733) (737) (727) 709 686 (730) (729) Annealing point (° C.) (785) (783) (787) (777) 760 — (780) (779) Glass transition point (° C.) (791) (787) (791) (781) (760) 737 (787) (786) Young's modulus (GPa) (85) (85) (84) (84.8) 81.3 83.9 (89) (85.0) T.sub.2 (° C.) (1710) (1714) (1731) (1696) (1692) 1634 (1641) (1678) T.sub.4 (° C.) (1342) (1343) (1355) (1330) (1318) 1274 (1299) (1322) Surface devitrification temp. T.sub.c (° C.) (≤1370) (≤1370) (≤1370) (≤1370) — 1265 — — Internal devitrification temp. T.sub.d (° C.) (≤1320) (≤1320) (≤1320) (≤1320) 1165 — — — Surface devitrification viscosity η.sub.c (≥10.sup.4.2) (≥10.sup.4.2) (≥10.sup.4.2) (≥10.sup.4.2) —   10.sup.4.1 — — (dPa .Math. s) Internal devitrification viscosity η.sub.d (≥10.sup.4.4) (≥10.sup.4.4) (≥10.sup.4.4) (≥10.sup.4.4)   10.sup.5.3 — — — (dPa .Math. s) Crystal growth rate (μm/hr) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) Sludge volume (ml) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) Etching rate (μm/min) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.6) Photoelastic constant (nm/MPa/cm) (26) (27) (27) (27) (29) (29) (27) (27) Specific modulus (MN .Math. m/kg) (33.2) (32.9) (32.0) (32.1) 31.8 33.3 (34.0) (32.2) Equivalent cooling rate (° C./min) 40 40 40 40 40 40 40 40 Compaction (ppm) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100)

TABLE-US-00003 TABLE 3 mol % Ex. 17 Ex. 18 Ex. 19 Ex. 20 Ex. 21 Ex. 22 Ex. 23 Ex. 24 SiO.sub.2 68.7 64.4 66.9 69.5 70.7 68.2 66.6 68.9 Al.sub.2O.sub.3 13.9 12.2 14.0 12.6 10.8 15.1 14.0 11.5 B.sub.2O.sub.3 0 4.2 1.5 0.3 0.3 0.5 1.3 0.6 MgO 7.0 9.0 5.9 6.2 5.3 4.6 6.2 5.6 CaO 5.0 7.1 5.9 6.4 10.2 3.5 5.7 8.9 SrO 0.0 0.7 4.0 0.9 0.3 5.6 1.2 2.8 BaO 5.0 1.2 1.1 3.1 1.6 1.8 4.1 1.3 Li.sub.2O 0.00 0.00 0.00 0.02 0.00 0.02 0.00 0.00 Na.sub.2O 0.02 0.03 0.08 0.02 0.05 0.06 0.03 0.08 K.sub.2O 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.05 F 0.00 0.33 0.17 0.00 0.17 0.00 0.33 0.00 Cl 0.10 0.53 0.18 0.35 0.35 0.00 0.00 0.00 SnO.sub.2 0.00 0.00 0.00 0.10 0.00 0.15 0.00 0.08 SO.sub.3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 As.sub.2O.sub.3 0.00 0.00 0.00 0.00 0.06 0.00 0.00 0.00 Sb.sub.2O.sub.3 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 P.sub.2O.sub.5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZrO.sub.2 0.03 0.03 0.01 0.10 0.03 0.10 0.04 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.23 0.00 0.00 Fe.sub.2O.sub.3 0.01 0.00 0.02 0.02 0.04 0.02 0.02 0.01 β-OH (/mm) 0.25 0.30 0.25 0.40 0.05 0.10 0.45 0.15 RO 17.0 18.2 16.9 16.8 17.5 15.5 17.3 18.6 MgO/CaO 1.40 1.26 1.00 0.97 0.51 1.31 1.11 0.63 Value of formula (A) 85.1 84.4 85.3 84.6 84.6 84.8 84.5 85.1 Value of formula (B) 752 693 731 744 738 750 735 730 Value of formula (C) 62.4 77.8 87.3 14.9 −20.5 81.5 96.9 14.6 Value of formula (D) 8.62 6.70 16.80 7.17 5.43 16.79 13.51 16.63 Value of formula (E) 4.18 4.70 4.57 3.00 2.02 4.50 5.01 3.44 Average thermal expansion 38.0 (37.3) (38.5) (38.1) (38.9) (38.6) (40.4) (43.3) coefficient (×10.sup.−7 / ° C.) Density (g/cm.sup.3) 2.65 (2.53) (2.59) (2.60) (2.54) (2.64) (2.64) (2.59) Strain point (° C.) 738 (689) (718) (731) (720) (745) (718) (702) Annealing point (° C.) 798 (742) (777) (790) (778) (805) (777) (759) Glass transition point (° C.) 791 (744) (773) (786) (774) (797) (774) (757) Young's modulus (GPa) 85.7 (84.8) (85.8) (85.4) (85.2) (85.5) (83.0) (83.3) T.sub.2 (° C.) 1729 (1635) (1693) (1756) (1762) (1737) (1706) (1712) T.sub.4 (° C.) 1358 (1273) (1331) (1365) (1361) (1368) (1335) (1330) Surface devitrification temp. T.sub.c (° C.) 1285 (1215) (1295) (1255) (1295) (1345) (1245) (1275) Internal devitrification temp. T.sub.d (° C.) 1235 (1175) (1235) (1235) (1295) (1295) (1195) (1245) Surface devitrification viscosity η.sub.c   10.sup.4.6 (10.sup.4.5) (10.sup.4.3) (10.sup.4.9) (10.sup.4.5) (10.sup.4.2) (10.sup.4.3) (10.sup.4.4) (dPa .Math. s) Internal devitrification viscosity η.sub.d   10.sup.5.1 (10.sup.4.9) (10.sup.4.8) (10.sup.5.1) (10.sup.4.5) (10.sup.4.6) (10.sup.5.2) (10.sup.4.7) (dPa .Math. s) Crystal growth rate (μm/hr) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) Sludge volume (ml) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) (≤30) Etching rate (μm/min) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) (2-4.5) Photoelastic constant (nm/MPa/cm) (26.2) (28.3) (27.1) (27.0) (27.6) (26.7) (26.5) (27.1) Specific modulus (MN .Math. m/kg) 32.3 (33.5) (33.1) (32.9) (33.5) (32.4) (31.4) (32.2) Equivalent cooling rate (° C./min) 40 40 40 40 40 40 40 40 Compaction (ppm) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100) (≤100)

[0221] In Examples 1-12 and Examples 17-24 in which the value of Formula (A) was 82.5 or larger, the Young's modulus was 83 GPa or larger. On the other hand, in Example 13 in which the value of Formula (A) was smaller than 82.5, the Young's modulus was smaller than 83 GPa.

[0222] In Examples 1-12 and Examples 17-24 in which the value of Formula (B) was 690 or larger, the strain point was 690° C. or higher. On the other hand, in Example 14 in which the value of Formula (B) was smaller than 690, the strain point was lower than 690° C.

[0223] In Examples 1-12 and Examples 17-24 in which the value of Formula (C) was 100 or smaller, the crystal growth rate was 100 μm/hr or lower. On the other hand, in Example 15 in which the value of Formula (C) was larger than 100, the crystal growth rate was higher than 100 μm/hr.

[0224] In Examples 1-12 and Examples 17-24 in which the value of Formula (D) was 20 or smaller, the sludge volume was 30 ml or smaller. On the other hand, in Example 16 in which the value of Formula (D) was larger than 20, the sludge volume was larger than 30 ml. In Examples 1-12, the surface devitrification viscosity η.sub.c was 10.sup.4.2 dPa.Math.s or higher.

[0225] In Example 14, the surface devitrification viscosity η.sub.c was lower than 10.sup.4.2 dPa.Math.s.

[0226] Although the invention has been described in detail with reference to the particular embodiments, it is apparent to those skilled in the art that various changes and modifications are possible without departing from the spirit and scope of the invention.

[0227] The present application is based on Japanese Patent Application No. 2019-20257 filed on Feb. 7, 2019, Japanese Patent Application No. 2019-51570 filed on Mar. 19, 2019, Japanese Patent Application No. 2019-141422 filed on Jul. 31, 2019, Japanese Patent Application No. 2019-186805 filed on Oct. 10, 2019, and Japanese Patent Application No. 2020-17691 filed on Feb. 5, 2020, the disclosures of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

[0228] The alkali-free glass according to the invention having the above-described features are suitable for uses such as substrates for displays, substrates for photomasks, substrates for supporting electronic devices, substrates for information recording media, substrates for planar antennas, substrates for dimming laminates, vehicular window glasses, acoustic vibration plates.