Abstract
A glass‐forming region was found in the 
system at a
mole ratio ≦3. Glass transition temperatures and conductivities at 25°C for the glasses are, respectively, expressed by
where 
, 
, and 
are mole fractions of each component in the glass. These equations show that 
and 
are primarily governed by the
content. From the results, it is speculated that a portion of the silver ions forms partially covalent bonds Ag‐O‐P. Conductivities at room temperature range from 10−3 to 10−2 Ω−1 cm−1. The advantages of glass formation for obtaining solid electrolytes with higher ionic conductivity are shown. Transport numbers of silver ions are approximately unity in the glasses.