Patent ID: 7160824

Claim:
A substantially non-crystalline glass fiber comprising about 0.5–30 wt % bismuth oxide, about 54–70 wt % silica, equal to or less than about 20 wt % sodium oxide, and Weight Percent (about) Al 2 O 3 1–5 wt % CaO 3–7 wt % MgO 1–5 wt % B 2 O 3 4–9 wt % Na 2 O 9–20 wt % K 2 O 0.0001–3 wt % NiO 0.0001–2 wt % BaO 0.0001–5 wt % Ag 2 O 0.0001–1 wt % F 2 0.0001–1 wt %.