На прикладі <$E gamma>-випромінювання від джерела <$E roman Co sup 60> досліджено ефект зовнішнього впливу на процес фізичного старіння халькогенідних стекол системи As - Se. Як результат радіаційної обробки із використанням методу диференціальної сканувальної калориметрії зафіксовано підвищення температури фазового переходу та площі ендотермічного піку в області фазового переходу скло - переохолоджена рідина для Se-збагачених стекол. Ці зміни пов'язують з додатковою <$E gamma>-активованою релаксацією склоподібної матриці до більш термодинамічно рівноважного стану переохолодженої рідини.

A newly modified correlation equation between defect-related positron lifetime <$Etau sub 2> (ns) defined within two-state model and corresponding radius <$ER( roman A back 45 up 35 symbol Р)> of freevolume positron traps in the full non-linear form <$Etau sub 2 ~=~0,285~cdot~left [ {1~-~r over {R~+~5,50}~+~1 over {2 pi }~cdot~sin (2 pi R "/" (R~+~5,50)} right ] sup -1> or simplified linear-approximated form <$Etau sub 2 ~=~0,212~cdot~(1~+~0,244~cdot~R)> is proved to account for compositional trends in void volume evolution of chalcogenide semiconductor compounds like binary As-S(Se) glasses. Specific chemical environment of free-volume voids associated with neighbouring network-forming polyhedrons is shown to play a decisive role in this correlation, leading to systematically enhanced estimated void sizes in comparison with typical molecular substrates, such as polymers.

Radiation-optical effects in vitreous chalcogenide semiconductors are comprehensively analyzed as resulting from both intrinsic and impurity-related redistribution of covalent chemical bonds known also together as destruction-polymerization transformations. Two types of experimental measuring protocols can be used to study radiation-induced effects within ех-situ direct or in-situ backward measuring chronology, the latter being more adequate for correct separated testing of competitive inputs from both channels of destruction-polymerization transformations. Critical assessment is given on speculations trying to ignore intrinsic radiation-structural transformations in As2S3 glass in view of accompanying oxidation processes. In final, this glass is nominated as the best model object among wide group of vitreous chalcogenide semiconductors revealing the highest sensitivity to radiation-induced metastability.

Principal difference in origin of high-order optical non-linearities caused by metallic nanoparticles such as Cu, Ag and Au embedded destructively in oxide- and chalcogenide-type glassy matrices has been analyzed from the viewpoint of semiempirical chemical bond approach. The numerical criterion has been introduced to describe this difference in terms of mean molar bond energies character for chemical interaction between unfettered components of destructed host glassy matrix and embedded guest atoms. It has been shown that "soft" covalent-bonded networks of chalcogenide glasses of As/Ge - S/Se systems differ essentially from glass-forming oxides like silica by impossibility to accommodate agglomerates of metallic nanoparticles. In contrast, such nanostructurized entities can be well stabilized in Cu-, Ag- or Au- embedded oxide glasses in full accordance with numerous experimental evidences. Recent unsubstantiated speculations trying to ascribe this ability to fully-saturated covalent matrices of chalcogenide glasses like As2S3 are analyzed and criticized as the misleading and inconclusive ones.

Індекс рубрикатора НБУВ: В371.211

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Шифр НБУВ: Ж16425 Пошук видання у каталогах НБУВ 
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