Patent ID: 9593034
Date: 2017-03-14
CPC Classifications: C03B,C03C

Claim:
1. A method for producing a blank of iron-doped glass having a high silicic acid content, an iron content of between 0.1% by wt. and 1% by wt., an internal transmission of not more than 40% in the infrared wavelength range of 800 nm to 2000 nm, and an internal transmission of at least 85% in the visible spectral range with wavelengths of 400 nm to 800 nm at a sample thickness of 1 mm, the method comprising: (a) producing an iron-doped SiO (b) drying the soot body to obtain a mean hydroxyl group content of less than 10 wt. ppm, and (c) vitrifying the soot body in an atmosphere having a reducing effect to form the blank of iron-doped glass having a high silicic acid content, wherein at least a part of the iron is reduced from the first oxidation state Fe