Concept of destruction-polymerization transformations was firstly developed in 1970-s to explain photo-induced effects in chalcogenide amorphous semiconductors (ChAS) [1]. These transformations are considered as bond-changing processes including destruction of initial bond(s) followed by formation of new one(s). Two atoms of network attain local coordination not obeying bond-saturation rule in the form of diamagnetic defect pair (over-coordinated-positive and undercoordinatednegative states). Alternatively, they can proceed as non-defect bond-switching, provided two bonds are simultaneously switched. Despite extensive research on radiation-induced phenomena since first observation of γ-irradiation hardening in ChAS by I.A. Domoryad in the earliest 1960-s [2], their microscopic nature has been discussible up to now. Recently, this problem was significantly complicated in view of numerous speculations mistakably attributed coordination defects to ChAS whichever their composition, prehistory and irradiation doses [3]. The role of DPT in radiation-induced effects was critically revised at the example of binary As-S ChAS. We estimated influence of energetic balances of different bond-switching reactions in a glassy matrix on the output of possible radiation-induced coordination topological defects. These estimations were experimentally verified for changes in fundamental optical absorption edge and positron annihilation lifetime spectra of As-S ChAS affected to high-energy γ-irradiation with 3 MGy dose. Obtained results were successfully explained by accepting that metastable pairs of overcoordinated positively-charged As and under-coordinated negatively-charged S atoms are formed owing to radiation-induced switching of heteropolar (As-S) covalent chemical bonds into homopolar (As-As) ones. These defect formation processes prevail near stoichiometric arsenic trisulphide composition in full agreement with predicted theoretical estimations. [1] S.B. Gurevich et al., Phys. Stat. Sol. A, 26 (1974) K127-K130. [2] I.A. Domoryad et al., Izv. AN Uzb.SSR. Ser. Fiz.-Mat. Nauk, 5 (1963) 87-89. [3] T.S. Kavetskyy, Abstr. VII Intern. School-Conf. “Actual Problems of Semicond. Phys.”. Drohobych, Ukraine: Sept. 28 – Oct. 1, 2010. P. 155-156.