The frequency-dependent dielectric dispersion of ZnO-Na2O-AI2O3-B2O3 (in mol％)glass prepared by the melt quenching technique is investigated in the temperature ranges from room temperature to 420 K.Dielectric relaxation has been analyzed based on the behavior of electric modulus behavior.An analysis of the real and imaginary parts of dielectric is performed assuming the ideal Debye behavior as confirmed by Cole-Cole plot.The activation energy associated with the dielectric relaxation determined from the electric modulus spectra was found to be 1.863 eV,which is close to that the activation energy for d.c.conductivity (1.871 eV),indicating the similar nature of relaxation and conductivity.