Ag+-K+ ion exchange is carried out by immersing a BK1 glass cylinder in a AgCl/ZnCl2 molten salt, The concentration profiles of silver and potassium in BK1 are measured and correlated using a mathematical model with self-diffusion coefficients as undetermined parameters, Self-diffusion coefficients of Ag+ and K+ are estimated from the ion concentration profiles after exchange for 6 days at 470, 500, 520, 540 degrees C, The activation energies of self-diffusion coefficients of K+ and Ag+ are found to be 22.4 and 35.4 kcal/mol, respectively.