A source of continuous scattering in fluoride glasses: Transition element phosphides

Continuous scattering in fluoride glasses is caused by numerous, uniformly distributed, submicron scattering centers. These scattering centers were individually isolated from the glass matrix, and characterized chemically and structurally. The particles were found to be transition element phosphides, usually phosphides of iron and nickel together with minor amounts of cobalt. The relative abundances of the transition elements varied from one particle to another. These scattering centers were most likely unmelted particles from the ZrF 4 batch.