Figure 4

Raman spectra of glasses with composition NBS20, I-free done in air or under pressure (HIP) or doped with ~1.9 and ~5 mol% of I2 (blue and green lines, respectively for NBS20-1.9I2 and NBS20-5.1I2).

Raman spectra of glasses with composition NBS20, I-free done in air or under pressure (HIP) or doped with ~1.9 and ~5 mol% of I2 (blue and green lines, respectively for NBS20-1.9I2 and NBS20-5.1I2).