Glass compositions with high refractive indexes and low densities
A glass composition having a content of SiO 2 that is greater than or equal to about 44.0 mol. % and less than or equal to about 60.0 mol. % and a content of ZnO that is less than or equal to about 1.0 mol. %. Additionally, the glass composition is essentially free of Pb and Bi. The glass composition also has a refractive index that is greater than or equal to 1.75 and a density that is less than or equal to about 4.5 g/cm 3 .
1. A glass composition comprising:
a content of SiO 2 that is greater than or equal to about 44.0 mol. % and less than or equal to about 60.0 mol. %;
a content of ZnO that is less than or equal to about 1.0 mol. %;
a content of MgO+CaO+SrO+BaO+ZnO that is greater than or equal to about 1.0 mol. % and less than or equal to about 30.0 mol. %; and
a content of TiO 2 that is less than or equal to about 20.0 mol. %,
wherein:
the glass composition is essentially free of Pb and Bi,
the glass composition has a refractive index n d greater than or equal to 1.75, and
the glass composition has a density less than or equal to about 4.5 g/cm 3 .
2. The glass composition according to claim 1 , wherein the refractive index n d of the glass composition is greater than or equal to 1.78.
3. The glass composition according to claim 2 , wherein the refractive index n d of the glass composition is greater than or equal to 1.80.
4. The glass composition according to claim 3 , wherein the refractive index n d of the glass composition is greater than or equal to 1.82.
5. The glass composition according to claim 1 , wherein the density of the glass composition is less than or equal to 4.0 g/cm 3 .
6. The glass composition according to claim 5 , wherein the density of the glass composition is less than or equal to 3.7 g/cm 3 .
7. The glass composition according to claim 1 , wherein the content of SiO 2 is greater than or equal to about 45.0 mol. % and less than or equal to about 55.0 mol. %.
8. The glass composition according to claim 1 , wherein the content of TiO 2 is greater than or equal to about 1.0 mol. % and less than or equal to about 18.0 mol. %.
9. The glass composition according to claim 1 , further comprising a content of Nb 2 O 5 that is greater than or equal to about 5.0 mol. % and less than or equal to about 25.0 mol. %.
10. The glass composition according to claim 1 , wherein the glass composition comprises a content of rare earth metal oxides that is less than or equal to about 25.0 mol. %.
11. The glass composition according to claim 1 , wherein the glass composition comprises a content of monovalent metal oxides that is less than or equal to about 25.0 mol. %.
12. The glass composition according to claim 1 , wherein the glass composition comprises a content of divalent metal oxides that is greater than or equal to about 1.0 mol. % and less than or equal to about 30.0 mol. %.
13. The glass composition according to claim 1 , wherein the glass composition comprises a total content of both monovalent metal oxides and divalent metal oxides that is greater than or equal to about 1.0 mol. % and less than or equal to about 35.0 mol. %.
14. The glass composition according to claim 1 , wherein the glass composition is essentially free of Fe, Cr, Cu, V, Mo, Co, and F.
15. The glass composition according to claim 1 , wherein the glass composition comprises a total content of Al 2 O 3 , B 2 O 3 , and P 2 O 5 that is less than or equal to about 0.1 mol. %.
16. The glass composition according to claim 1 , wherein the glass composition satisfies the following condition: refractive index−1.42−0.10×density (g/cm 3 )>0.00.
17. The glass composition according to claim 1 , wherein the glass composition satisfies the following condition: refractive index−2.21+0.0086×SiO 2 (mol. %)>0.00.
18. A glass composition comprising:
a content of SiO 2 that is greater than or equal to about 35.0 mol. % and less than or equal to about 60.0 mol. %; and
a content of MgO+CaO+SrO+BaO+ZnO that is greater than or equal to about 1.0 mol. % and less than or equal to about 30.0 mol. %,
wherein the glass composition satisfies the following conditions:
refractive index−1.42−0.10×density (g/cm 3 )>0.00, and
refractive Index−2.21+0.0086×SiO 2 (mol. %)>0.00.
19. A glass composition comprising:
a content of SiO 2 that is greater than or equal to about 35.0 mol. % and less than or equal to about 60.0 mol. %;
a content of MgO+CaO+SrO+BaO+ZnO that is greater than or equal to about 1.0 mol. % and less than or equal to about 30.0 mol. %; and
a content of TiO 2 that is less than or equal to about 20.0 mol. %,
wherein the glass composition satisfies the following condition:
refractive index−2.21+0.0086×SiO 2 (mol. %)>0.00.