Absorption loss due to complex anions in fluorozirconate glasses

A fluorozirconate glass ZBL-3 with the molar composition 0.62 ZrF4, 0.33 BaF2, 0.05 LaF3was doped with various amounts of NaPO3, KHSO4, and also with Na2CO3, NaNO3and TiOF2. Characteristic absorption bands were observed at 2100 cm^-1and 1640 cm^-1for phosphates and 2150, 2350, and 1600 cm^-1for sulfates. The absorption resulting from 1 ppm of P is 900 dB/km at 2100 cm^-1while it is slightly lower for 1 ppm of S. Carbonates and nitrates are decomposed in the glass melt and result in a small shift of the infrared multiphonon absorption.