Nanostructured glasses and vitroceramics that are transparent in visible and infra-red ranges

Abstract

The present invention relates to novel vitroceramic or lens compositions that are nanostructured and transparent or translucent, including at least 97%, such as 97% to 100%, preferably 99% to 100%, by weight, relative to the total weight of the material, of a composition having the following formula I: (GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k (I) where Oxy.sub.1 is an oxide selected from ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, TiO.sub.2, BiO.sub.1.5, AgO, CaO, MnO, or a mixture thereof, selected preferably from ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, AgO, CaO, MnO, or a mixture thereof, selected more preferably from ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, Or a mixture thereof, selected most preferably from ZnO, MgO, AgO, NbO.sub.2.5, or a mixture thereof, and Oxy.sub.2 is an oxide selected from Na.sub.2O, K.sub.2O or a mixture thereof, Oxy.sub.2 is preferably Na.sub.2O, and x, y, z, a, b and k are as defined in claim 1, to the manufacturing method thereof and to the uses thereof in the field of optics.

Claims

1. A nanostructured vitroceramic, either transparent or translucent, with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, containing 97% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, TiO.sub.2, BiO.sub.1.5, AgO, CaO, MnO, or a mixture thereof, and Oxy.sub.2 is an oxide selected from Na.sub.2O, K.sub.2O, or a mixture thereof, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z20, x, y, z are such that 40x+y+z98, 0.1x50, 0b35, and 0k7, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

2. Nanostructured glass, either transparent or translucent, with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, containing 97% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, TiO.sub.2, BiO.sub.1.5, AgO, CaO, MnO, or a mixture thereof, and Oxy.sub.2 is an oxide selected from among Na.sub.2O, K.sub.2O or a mixture thereof, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z20, x, y, z are such that 40x+y+z98, 0.1x50, 0b35, and 0k7, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

3. Vitroceramic according to claim 1, wherein x and y are such that x+y40, in particular x+y50.

4. Vitroceramic according to claim 1, wherein x is equal to 0 and 40y60 or 43y55.

5. Vitroceramic according to claim 1, wherein y is equal to 0 and 50x98 and z is equal to 0.

6. Vitroceramic or glass according to claim 1, wherein x and y are each independently 10x80; and 10y60, and x and y are such 50x+y95, 60x+y98 or 80x+y95.

7. Vitroceramic according to claim 1, containing dopants in addition to the composition formula (I) in order to attain 100% per unit mass.

8. Manufacturing process of a nanostructured glass according to claim 2, comprising the successive steps of: 1melting of initial oxides, or if applicable precursors thereof, present in powder form, at a temperature within the range between 900 C. and 1700 C.; 2cooling, producing a transparent or translucent nanostructured glass with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, containing 97% to 100% by weight, in relation to the overall weight of the glass, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, TiO.sub.2, BiO.sub.1.5, AgO, CaO, MnO, or a mixture thereof, and Oxy.sub.2 is an oxide selected from among Na.sub.2O, K.sub.2O or a mixture thereof, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z20, 40x+y+z98, 0.1x50, 0b35, and 0k7, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

9. Manufacturing process of a nanostructured vitroceramic according to claim 1, comprising the successive steps of: 1manufacture of a transparent or translucent nanostructured glass with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, and containing 97% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, NbO.sub.2.5, WO.sub.3, NiO, SnO, TiO.sub.2, BiO.sub.1.5, AgO, CaO, MnO, or a mixture thereof, and Oxy.sub.2 is an oxide selected from Na.sub.2O, K.sub.2O or a mixture thereof, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z20, 40x+y+z98, 0.1x50, 0b35, and 0k7, and x, y, z, a, b and k are such that x+y+z+a+b+k=100, according to a process comprising the successive steps of: melting of the initial oxides, or if applicable their precursors, present in powder form, at a temperature within the range between 900 C. and 1700 C., and then cooling; 2thermal crystallisation treatment of the glass at a temperature within the range between 400 C. and 900 C., for a period within the range between 15 minutes and 48 hours.

10. Use of a glass according to claim 2, for the manufacture of optical material, including masses, powders, fibres or layers; for the manufacture of material for medical imaging, for lighting or for displays; or for laser marking.

11. The nanostructured vitroceramic of claim 1, containing 99% to 100% by weight in relation to the overall weight of the material, of a composition of the formula I.

12. The nanostructured vitroceramic of claim 1, wherein Oxy.sub.1 is an oxide selected from ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof.

13. The nanostructured vitroceramic of claim 1, wherein Oxy.sub.2 is Na.sub.2O.

14. The nanostructured vitroceramic of claim 1, wherein 0z10.

15. The nanostructured vitroceramic of claim 1, wherein 0.5a25.

16. The nanostructured vitroceramic of claim 1, wherein 1b25.

17. The nanostructured vitroceramic of claim 1, wherein 0k5.

18. A nanostructured vitroceramic, either transparent or translucent, with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, containing 99% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof, and Oxy.sub.2 is Na.sub.2O, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z10, 40x+y+z98, 0.5x25, 1b25, and 0k5, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

19. The nanostructured glass of claim 2, containing 99% to 100% by weight in relation to the overall weight of the material, of a composition of the formula I.

20. The nanostructured glass of claim 2, wherein Oxy.sub.1 is an oxide selected from ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof.

21. The nanostructured glass of claim 2, wherein Oxy.sub.2 is Na.sub.2O.

22. The nanostructured glass of claim 2, wherein 0z10.

23. The nanostructured glass of claim 2, wherein 0.5a25.

24. The nanostructured glass of claim 2, wherein 1b25.

25. The nanostructured glass of claim 2, wherein 0k5.

26. Nanostructured glass, either transparent or translucent, with essentially zero Li.sub.2O content and zero Al.sub.2O content, containing 99% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected preferably from ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof, and Oxy.sub.2 is Na.sub.2O, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z10, x, y, z are such that 40x+y+z98, 0.5x25, 1b25, and 0k5, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

27. Manufacturing process of a nanostructured glass according to claim 26, comprising the successive steps of: 1melting of initial oxides, or if applicable precursors thereof, present in powder form, at a temperature within the range between 900 C. and 1700 C.; 2cooling, producing a transparent or translucent nanostructured glass with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, containing 99% to 100% by weight, in relation to the overall weight of the glass, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof, and Oxy.sub.2 is Na.sub.2O, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z10, x, y, z are such that 40x+y+z98, 0.5x25, 1b25, and 0k5, and x, y, z, a, b and k are such that x+y+z+a+b+k=100.

28. The process according to claim 9, wherein the thermal crystallisation treatment is performed at a temperature within the range 600 C. and 800 C., for a period within the range between 15 minutes and 6 hours.

29. Manufacturing process of a nanostructured vitroceramic according to claim 1, comprising the successive steps of: 1manufacture of a transparent or translucent nanostructured glass with essentially zero Li.sub.2O content and zero Al.sub.2O.sub.3 content, and containing 99% to 100% by weight in relation to the overall weight of the material, of a composition of the following formula I:
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I) where Oxy.sub.1 is an oxide selected from among ZnO, MgO, AgO, BiO.sub.1.5, NbO.sub.2.5, or a mixture thereof, and Oxy.sub.2 is Na.sub.2O, and 0x98, and 0y60, and x and y are not simultaneously zero, and 0z10, x, y, z are such that 40x+y+z98, 0.5x25, 1b25, and 0k5, and x, y, z, a, b and k are such that x+y+z+a+b+k=100, according to a process comprising the successive steps of: melting of the initial oxides, or if applicable their precursors, present in powder form, at a temperature within the range between 900 C. and 1700 C., and then cooling; 2thermal crystallisation treatment of the glass at a temperature within the range between 600 C. and 800 C., for a period within the range between 15 minutes and 6 hours, and preferably between 30 minutes and 2 hours.

30. Glass according to claim 2, wherein x and y are such that x+y40, in particular x+y50.

31. Glass according to claim 2, wherein x is equal to 0 and 40y60 or 43y55.

32. Glass according to claim 2, wherein y is equal to 0 and 50x98 and z is equal to 0.

33. Vitroceramic or glass according to claim 2, wherein x and y are each independently 10x80; and 10y60; and x and y are such that 50x+y95, 60x+y98 or 80x+y95.

34. Glass according to claim 2, containing dopants in addition to the composition formula (I) in order to attain 100% per unit mass.

35. Use of a vitroceramic according to claim 1, for the manufacture of optical material, including masses, powders, fibres or layers; for the manufacture of material for medical imaging, for lighting or for displays; or for laser marking.

Description

DESCRIPTIONS OF THE FIGURES

(1) FIG. 1: Transmittance curves (as %, y-coordinate) according to wavelength (as nm, x-coordinate) of glasses (solid line) and vitroceramics (stippled line) of (a) germanate (78GeO.sub.2-9.8ZnO-9.8GaO.sub.3-2.4Na.sub.2O), and (b) silicate (55SiO.sub.2-5Na.sub.2O-23Ga.sub.2O.sub.3-17ZnO). Photographs of transparent nanostructured glasses (On the left) and vitroceramics (at right), developed according to the invention, are also shown.

(2) FIG. 2: Negatives of electronic microscopy in transmission (MET) of a glass and vitroceramic of the composition: 84GeO.sub.2-6Ga.sub.2O.sub.3-10ZnO (segregation of the nucleation/growth type). On the left, negative of nanostructured glass; at right, negative of the equivalent vitroceramic, obtained through thermal crystallisation treatment. The negatives of associated electronic diffraction are shown as an inset.

(3) FIG. 3: Negative of electronic microscopy in transmission (MET) of a nanostructured glass (separation of the spinel phase) of the composition 80GeO.sub.2-7.5Ga.sub.2O.sub.3-12.5ZnO.

(4) FIG. 4: Negatives of electronic microscopy in transmission (MET) of a glass and a vitroceramic of the composition: 55SiO.sub.2-5Na.sub.2O-20Ga.sub.2O.sub.3-20AnO. On the left, negative of the nanostructured glass (separation of the spinel phase); at right, negative of equivalent vitroceramic, obtained through thermal crystallisation treatment of the glass.

(5) FIG. 5: Negatives of electronic microscopy in transmission (MET) of a glass and of a vitroceramic of the composition: 90GeO.sub.2-3.75Ga.sub.2O.sub.3-6.25Bi.sub.2O.sub.3. On the left, negative of the nanostructured glass (separation of nucleation-growth phase with nanostructuring of very small size, in the order of a few nm); at right, negative of the equivalent vitroceramic, obtained through thermal crystallisation treatment of the glass.

(6) FIG. 6: Spectrum of photoluminscence in the infra-red (.sub.excitation=980 nm) of a nanostructured vitroceramic of the composition: 88GeO.sub.2-5.4Ga.sub.2O.sub.3-6.6ZnO, doped with nickel (Ni.sup.2+, 0.05 by weight). The x-coordinate axis depicts wavelengths in nm, while the y-coordinate axis depicts intensity, expressed as an arbitrary unit.

(7) FIG. 7: Spectrum of conversion photoluminscence at a wavelength that is shorter than that of the emission (up-conversion), for .sub.excitation=980 nm of a nanostructured glass of the composition 88GeO.sub.2-5.4Ga.sub.2O.sub.3-6.6ZnO, doped with 0.5 per unit mass of erbium (Er.sup.3+). The x-coordinate axis depicts wavelengths in nm, while the y-coordinate axis depicts intensity, expressed as an arbitrary unit.

(8) FIG. 8: Spectrum of excitation (On the left) and emission spectrum (at right) of a vitroceramic and a glass of nanostructured germanate of composition 90GeO.sub.2-6.25ZnO-3.75Ga.sub.2O.sub.3, doped with terbium (Tb.sup.3+/Tb.sup.4+, 0.25 by weight). The x-coordinate axis depicts wavelengths in nm, while the y-coordinate axis depicts intensity, expressed as an arbitrary unit. In the case of the glass, the excitation spectrum corresponds to the emission as measured at 542 nm, while the emission spectrum corresponds to excitation at a wavelength of 260 nm. In the case of the vitroceramic, the excitation spectrum corresponds to the emission as measured at 450 nm, while the emission spectrum corresponds to excitation at a wavelength of 286 nm. The excitation curve of the glass (solid line) shows a maximum for around =240 nm, whereas the excitation curve for the vitroceramic (stippled line) shows a maximum for around =280 nm. The emission curve for the glass (solid line) shows four slight peaks, with an intense peak at around 550 nm. The vitroceramic's emission curve (stippled line) shows a broad peak, including a gentle shoulder towards 550 nm.

(9) FIG. 9: Spectrum of excitation (On the left) and spectrum of emission (at right) of a nanostructured silicate vitroceramic and glass with the identical composition, doped with manganese. (Mn.sup.2+, 0.1 by weight). The x-coordinate axis depicts wavelengths in nm, while the y-coordinate axis depicts intensity, expressed as an arbitrary unit. In the case of the glass, the excitation spectrum corresponds to the emission as measured at 619 nm, while the emission spectrum corresponds to excitation at a wavelength of 272 nm. In the case of the vitroceramic, the excitation spectrum corresponds to the emission as measured at 645 nm, while the emission spectrum corresponds to excitation at a wavelength of 272 nm. The excitation curve for the glass (solid line) shows a maximum for around =275 nm with high intensity, whereas the excitation for the vitroceramic (stippled line) shows a maximum for around =270 nm, with a lower intensity than that of the glass. The emission curve of the glass (solid line) shows broad peaks, with a maximum intensity at around =625 nm, which is below that of the vitroceramic (the signal of the glass is less intense than that of the vitroceramic). The vitroceramic's emission curve (stippled line) also shows broad peaks, with a maximum intensity for around =530 nm.

EXAMPLES

(10) The following examples are intended to illustrate the invention in greater detail, but are by no means exhaustive. In particular, the methods to be described below are the laboratory procedures, which can readily be adapted to an industrial scale by those skilled in the art.

(11) Powders of oxide precursors are first weighed out in the desired proportions, and then ground and mixed into a mortar. Where carbonates are used, a decarbonisation step is carried out. The glasses and vitroceramics are then synthesised from the mixtures prepared as already described, by melting in a conventional oven (fitted with heating resistors) at a temperature within the range between 900 C. and 1700 C., followed by cooling of the liquid. Temperatures of vitreous production decrease with the increase in germanium oxide content. In the case of vitroceramics, a thermal crystallisation treatment is then carried out in a conventional laboratory oven at a temperature within the range between 400 C. and 900 C.

(12) Example of Laboratory Production of a Glass and its Equivalent Vitroceramic, Adapted for Implementation on an Industrial Scale.

(13) Glass Production Method

(14) In order to prepare 2 g glass of the molar composition 78.04GeO.sub.2-9.76ZnO-9.76Ga.sub.2O.sub.3-2.44Na.sub.2O, the following weighing operations are carried out:

(15) 1.4927 g GeO.sub.2

(16) 0.1452 g ZnO

(17) 0.3344 g Ga.sub.2O.sub.3

(18) 0.0493 g Na.sub.2CO.sub.3.

(19) After weighing out individually, the complete set of precursors is ground and mixed thoroughly into an agate mortar. The mixture is then placed in a platinum crucible.

(20) In view of the presence of sodium carbonate, the mixture then undergoes decarbonisation treatment (gradual heating (10 C./min.) to 900 C. and held at that temperature for 6 hours, then chilled in the oven, (which has been shut down) in order to eliminate the CO.sub.2 present in the sodium carbonate, thereby making it possible to obtain the sodium oxide of the composition.

(21) After the decarbonisation treatment (which is applied only where there is carbonate in the mixture of precursors), the platinum crucible is placed in a hot muffle furnace at 1300 C. and heated for 30 minutes. On completion of heating, the mixture cast is removed from the oven and chilled in the crucible (chilled atmospherically).

(22) In this way we obtain a glass according to the invention, of the formula 78.04GeO.sub.2-9.76ZnO-9.76Ga.sub.2O.sub.3-2.44Na.sub.2O.

(23) Method of Vitroceramic Production

(24) The glass, synthesised as already shown, then undergoes thermal crystallisation treatment in a tubular oven (for 3 hours at 615 C.), which will produce a transparent nanostructured vitroceramic.

(25) Implementation on an Industrial Scale

(26) In the case of an industrial method, some steps can be amended to take account of energy-consumption considerations. For example, the decarbonisation phase could be merged directly into the heating phase (one step). Conventional refining additives, familiar in the field, may be also be added to facilitate fusion of the glass and the elimination of bubbles. On the other hand, the annealing of crystallisation could be done while cooling the glass, for example directly in a mould containing the ground glass (mould kept for 3 hours in an oven at 615 C.).

(27) Transmission of glasses and vitroceramics was measured in the 250 nm-8000 nm spectral domain, using a dual-beam spectrophotometer.

(28) Glasses and vitroceramics were synthesised using a similar method, corresponding to the compositions of formula (I):
(GeO.sub.2).sub.x(SiO.sub.2).sub.y(B.sub.2O.sub.3).sub.z(Ga.sub.2O.sub.3).sub.a(Oxy.sub.1).sub.b(Oxy.sub.2).sub.k(I),

(29) in which:

(30) TABLE-US-00001 Germanate b k x y z A (Oxy 1) (Oxy2) 98GeO.sub.20.75Ga.sub.aO.sub.31.25ZnO 98 0 0 0.75 1.25 0 (ZnO) 60GeO.sub.23Na.sub.2O13.9Ga.sub.2O.sub.323.1ZnO 60 0 0 13.9 23.1 3 (ZnO) (Na.sub.2O) 90GeO.sub.23.75Ga.sub.2O.sub.36.25AgO 90 0 0 3.75 6.25 0 (AgO) 84GeO.sub.26Ga.sub.2O.sub.310ZnO 84 0 0 6 10 0 (ZnO) 60GeO.sub.23Na.sub.2O13.9Ga.sub.2O.sub.323.1MgO 60 0 0 13.9 23.1 3 (MgO) (Na.sub.2O) 92GeO.sub.22Ga.sub.2O.sub.36Bi.sub.2O.sub.3 86.8 0 0 1.9 11.3 0 (BiO.sub.1.5) 87GeO.sub.21K.sub.2O3Ga.sub.2O.sub.39WO.sub.3 87 0 0 3 9 1 (WO.sub.3) (K.sub.2O) 90GeO.sub.23.75Ga.sub.2O.sub.36.25ZnO 90 0 0 3.75 6.25 0 (ZnO) 90GeO.sub.23.75Ga.sub.2O.sub.36.25Bi.sub.2O.sub.3 84.7 0 0 3.5 11.8 0 (BiO.sub.1.5) 88GeO.sub.25.4Ga.sub.2O.sub.36.6ZnO 88 0 0 5.4 6.6 0 (ZnO) 78.04GeO.sub.29.76ZnO9.76Ga.sub.2O.sub.32.44Na.sub.2O 78.04 0 0 9.76 9.76 2.44 (ZnO) Na.sub.2O b k x y z a (Oxy.sub.1) (Oxy.sub.2) Silicate 55SiO.sub.25Na.sub.2O23Ga.sub.2O.sub.317ZnO 0 55 0 23 17 5 (ZnO) (Na.sub.2O) 44SiO.sub.26Na.sub.2O25Ga.sub.2O.sub.325 MgO 0 44 0 25 25 6 (MgO) (Na.sub.2O) 60SiO.sub.25Na.sub.2O1K.sub.2O20Ga.sub.2O.sub.310ZnO4Nb.sub.2O.sub.5 0 57.8 0 19.2 17.3 5.7 (7.7 (4.8 NbO.sub.2.5, Na.sub.2O, 9.6 0.9K.sub.2O) (ZnO) 55SiO.sub.25Na.sub.2O20Ga.sub.2O.sub.320ZnO 0 55 0 20 20 0 (ZnO) Silicogermanate 42GeO.sub.250SiO.sub.23Ga.sub.2O.sub.35ZnO 42 50 0 3 5 0 (ZnO) 70GeO.sub.210SiO.sub.22Na.sub.2O4Ga.sub.2O.sub.34Bi.sub.2O.sub.3 67.4 9.6 0 3.8 7.7 1.9 (BiO.sub.1.5) (Na.sub.2O) 50GeO.sub.230SiO.sub.210B.sub.2O.sub.35Ga.sub.2O.sub.35ZnO 50 30 10 5 5 0 (ZnO)

(31) Summary table of synthesised compositions.

(32) Where appropriate, dopants were added to these compositions. Dopants were added during the manufacturing process for doped glasses and vitroceramics in powder form, then ground and mixed with other powders of precursors, as described above in the example of glass synthesis of the formula 78.04GeO.sub.2-9.76ZnO-9.76Ga.sub.2O.sub.3-2.44Na.sub.2O.

(33) Photographs of glasses and vitroceramics of (a) germanate (78GeO.sub.2-9.8ZnO-9.8Ga.sub.2O.sub.3-2.4Na.sub.2O), and (b) silicate (55SiO.sub.2-5Na.sub.2O-23Ga.sub.2O.sub.3-17ZnO) are shown in FIG. 1. These illustrate the transparency of the materials according to the invention.

(34) In addition, FIG. 2 shows the negatives of electronic microscopy in transmission (MET) of a glass and vitroceramic of the composition: 84GeO.sub.2-6Ga.sub.2O.sub.3-10ZnO. The negative of glass reveals segregation of the nucleation/growth type, of nanometric size.

(35) FIG. 3 shows the negatives of electronic microscopy in transmission (MET) of a nanostructured glass with spinel-phase separation, of the composition 80GeO.sub.2-7.5Ga.sub.2O.sub.3-12.5ZnO.

(36) With regard to FIG. 4, it depicts compositions of a glass and vitroceramic of the composition: 55SiO.sub.2-5Na.sub.2O-20Ga.sub.2O.sub.3-20ZnO (negatives of electronic microscopy in transmission (MET). In this instance, the glass shows spinel-phase separation of nanometric size.

(37) FIG. 5 shows negatives of electronic microscopy in transmission (MET) of a nanostructured glass with nucleation-growth phase separation, with nanostructuring of a very small size in the order of a few nm, and a vitroceramic of the composition 90GeO.sub.2-3.75Ga.sub.2O.sub.3-6.25Bi.sub.2O.sub.3.

(38) FIG. 6 describes a spectrum of photoluminescence in the infra-red (.sub.excitation=980 nm) of a nanostructured vitroceramic of the composition: 88GeO.sub.2-5.4Ga.sub.2O.sub.3-6.6ZnO, doped with nickel (Ni.sup.2+, 0.05% by weight).

(39) FIGS. 7 to 9 show spectra depicting the optical properties of glasses and vitroceramics of the composition: 88GeO.sub.2-5.4Ga.sub.2O.sub.3-6.6ZnO, doped with 0.5% per unit mass of erbium (Er.sup.3+), 90GeO.sub.2-6.25ZnO-3.75Ga.sub.2O.sub.3, doped with terbium (Tb.sup.3+/Tb.sup.4+, 0.25% by weight), and 90GeO.sub.2-6.25ZnO-3.75Ga.sub.2O.sub.3, doped with manganese (Mn.sup.2+, 0.1% by weight).