Effect of Atmosphere on the Electrical Conductivity of Sodium Tungstophosphate Glasses

The dc electrical conductivity of sodium tungstophosphate glasses was measured as a function of glass composition, melting history, and ambient atmosphere. The color of the glasses was a strong function of both glass composition and melting history. The electrical conductivity was found to be strongly dependent upon the concentration of protons in the surrounding atmosphere. The colorless glasses were found to be electrochromic only so long as protons were present in the atmosphere. A model is suggested to explain these results.