High transmittance glass

1. A high transmittance glass, consisting essentially of:

SiO 2

65 to 75 weight percent;

Na 2 O

10 to 20 weight percent;

CaO

5 to 15 weight percent;

MgO

0 to 5 weight percent;

Al 2 O 3

0 to 5 weight percent;

K 2 O

0 to 5 weight percent;

MnO 2

0.1 to 0.6 weight percent;

FeO

0.0010 to 0.0030 weight percent;

Fe 2 O 3 (total iron)

0.001 to 0.03 weight percent;

wherein the glass has a redox ratio in the range of 0.1 to 0.4.

2. The glass of claim 1 , wherein the MnO 2 is in the range of 0.15 to 0.25 weight percent.

3. The glass of claim 1 , wherein the MnO 2 is in the range of 0.2 to 0.25 weight percent.

4. The glass of claim 1 , wherein the glass has a redox ratio in the range of 0.1 to 0.3.

5. The glass of claim 1 , wherein the glass has a redox ratio in the range of 0.2 to 0.3.

6. The glass of claim 1 , wherein the glass has a redox ratio in the range of 0.2 to 0.25.

7. The glass of claim 1 , wherein the total iron is less than 0.02 weight percent.

8. A high transmittance glass, consisting essentially of:

SiO 2

71 to 75 weight percent;

Na 2 O

13 to 14 weight percent;

CaO

10 to 11 weight percent;

MgO

2 to 3 weight percent;

Al 2 O 3

0.02 to 0.05 weight percent;

K 2 O

0.01 to 0.02 weight percent;

MnO 2

0.18 to 0.25 weight percent;

FeO

15 to 18 ppm;

Fe 2 O 3 (total iron)

0.007 to 0.008 weight percent;

wherein the glass has a redox ratio in the range of 0.15 to 0.25.