Atomic structure of barium tin phosphate glasses

Tin phosphate glasses are an alternative as lead-free glasses with zero photoelastic constant (PEC) for fiber applications. A second modifier oxide is added for improving the corrosion resistance and adjusting the right mixture for zero PEC value. An important result of the first proposal was the detected change of the Sn-O coordination number from three to four with ZnO additions. Here, BaO is used as second modifier oxide that guaranties even better corrosion resistance and shows similar refractive index with higher Abbe number (lower dispersion). Here, the determination of the Sn-O distances does not need combination with X-ray diffraction because the distances do not overlap with others (O-O and Ba-O). GEM allows excellent distance resolution. Two compositional series with 40 and 33mol% P2O5 and increasing BaO content are planned. Several properties of samples are already collected.