The purpose of the work is to prevent the destruction of elements from optical ceramics of de-vices by improving the properties of the surface layers of the elements and increasing their resistance to external thermo-influences by means of preliminary electron beam processing. As a result of conducted experimental researches it was established that after preliminary pro-cessing of working surfaces of elements from optical ceramics by a moving electronic beam for ranges of changes of its parameters (density of thermal influence nF = 106…1,6·107 W/m2 and the speed of its movement V = 10-3…10-1 m/s) the microhardness of the surface rises in 1,5 ... 1,7 times; in the sur-face layers of 40 ... 60 μm thickness, compressive thermosetting voltages are formed in magnitude 25…90 MPa, which lead to the formation of reinforced layers in the thickness up to 210 ... 230 mi-crons. It was obtained that the improvement of the properties of the surface layers of optical elements after their electron beam processing leads to an increase in the stability of the elements to external thermo-influences: the critical values of the external heat fluxes and the time of their actions, which lead to the destruction of the elements, are increased in 2 ... 4 times; while increasing the external pressure from 105 Pa to 107 Pa reduces the indicated critical values of parameters in 1,3 ... 1,7 times; the value of the maximum allowable thermo-elastic tensions in optical elements processed by an elec-tron beam is increased in 1,8 ... 2,7 times, for the ranges of temperature changes of heating 300 ... 1200 K.