Formation of Waveguide Layers on the Surface of K8 Glass Produced by Thermoradiation Ion Exchange

Abstract—The low-temperature heat treatment of K8 glass is carried out at temperatures of 350–500°C in alkaline melts of NaNO₃ and CsNO₃ salts in the field of gamma radiation from the ⁶⁰Co source at the dose rate of 3000 R/s and also outside the field. Under the influence of thermoradiation treatment due to the ${\text{Na}}_{{{\text{glass}}}}^{ + }$ ↔ ${\text{Cs}}_{{{\text{melt}}}}^{ + }$ ion-exchange diffusion, mechanical compressive stresses are created in the surface layer of the glass, which lead to the formation of a waveguide layer of the given thickness and an increase in the refractive index (RI) increment, the number of waveguide modes, and the depth of the waveguide layer.