Filter glasses for photometric application

A program has been undertaken to investigate the preparation of new filter glasses for photometric use. By changing the composition of different base glasses containing small amounts of glass coloring metal oxides, it was possible to obtain new glasses with interesting transmittance properties. Gaussian-type spectral transmittance curves were obtained showing characteristics similar to some CIE standard photometric functions such as V(lambda), V'(lambda), and x (lambda). By slight alterations to the constituents and preparation procedure, it was possible to obtain shifts in the spectral transmittances enabling close approximation to some standard distributions. Tellurite and phosphate glasses with small quantities of metal oxides proved the most successful for this purpose.