Thermodynamic properties of amorphous solids: The electrochemical approach

In the present contribution are critically analyzed and reexamined the possibilities to determine the thermodynamic properties of amorphous solids, of defect crystals and of glasses by means of electrochemical methods. After detailed theoretical considerations performed in the framework of the thermodynamics of irreversible processes it is demonstrated how the most significant thermodynamic parameters of amorphous systems with frozen-in structure—their configurational enthalpy and entropy ΔH_g and ΔS_g—can be electrochemically measured, when the systems under investigation are first order (electron) conductors, capable of forming the electrodes in a glass → crystal Galvanic cell. We refer here to existing classical experimental results with two such systems: vitreous Sb (so-called explosive antimony) and glassy carbon resins both used to demonstrate the applicability of the theoretical considerations developed. Results with several Metglass alloy systems (Ni/P, Fe, Ni/P, B, Co/B and Cu/Ti), obtained via corrosion potentio-dynamic electrochemical measurements are also summarized and used to estimate the thermodynamic properties of variously treated glass-forming systems. The electrochemical evidence analyzed clearly demonstrates in its integrity the particular, frozen-in nature of the basic thermodynamic parameters in the considered glass systems (ΔHg ≈ const > 0, ΔSg ≈ const > 0) as this is expected to be both from classical theory and from known calorimetric measurements. The contribution of direct glass/crystal Voltaic contacts to the thermodynamic properties of electrochemical cells with glassy or vitro-crystalline electrodes is also considered in details. Possible technical applications of Galvanic and Voltaic potentials, determined by glassy or vitro-crystalline electrode materials, including existing conventional battery systems and other horizons, opened to discussion by the present theoretical approach are also outlined.