Maxwell-Wagner effect and second optical harmonic generation in a glass via field-assisted ion exchange

Abstract

Maxwell-Wagner charge and electric field formation, as well as the associated generation of the electric field induced second harmonic (SH), are firstly studied in soda-lime glass structures produced with electric field assisted potassium-to-sodium ion exchange. The measured Maxwell-Wagner charge accumulation times are in the range of minutes and depend on the thickness of subsurface region enriched with potassium ions. The dynamics of the SH signal, which corresponds to the dynamics of Maxwell-Wagner charge accumulation in the specimens, made it possible to estimate the electrical conductivity and, consequently, mobility of charge carriers of both the original glass containing mainly sodium ions and the ion-exchanged region containing potassium ions. Estimated ionic mobilities are ∼1.7∙10⁻²² m²/(V∙s) and ∼1.7∙10⁻²⁰ m²/(V∙s) at room temperature for potassium and sodium ions, respectively. This data corresponds to those known for soda-lime glasses. At 60 °C mobility values are expectedly higher: ∼14∙10⁻²² m²/(V∙s) and ∼9∙10⁻²⁰ m²/(V∙s), respectively. It is shown that the Maxwell-Wagner effect and the associated SH generation in glasses represent another tool for characterizing ion-exchange modification of glass properties.