Characterization and structure of a fiber of BaO-SnO-P2O5-B2O3 glass with a very small photoelastic constant

The optical properties of a BaO-SnO-P2O5-B2O3 glass fiber with a very small photoelastic constant are characterized, and its phosphate and borate structure is studied via micro Raman and 31P and 11B magic-angle-spinning nuclear magnetic resonance spectrometry. The characteristics of the lead-free borophosphate fiber are equivalent to those of the developed lead silicate fiber used as an optical component in current transducers. The azimuth of polarized light is maintained through the new fiber with a very small photoelastic constant, which represents a potential new current transducer without hazardous elements. The elucidated structural units of the fiber are pyro- and metaphosphates and tetrahedral borate, which resemble the structural units of a preform glass.