Molecular and ionic species of nitrogen oxides have been injected, formed, and then trapped within a borosilicate glass during a thermal poling process. This original observation denotes a new aspect of poling mechanisms for ionic glasses. For each poled borosilicate glasses studied, compositional, structural, and second harmonic generation profiles of their subanodic polarized layers have been characterized. A description of the space charge implementation process, involving interactions between charged and chemically active species formed both within plasma discharges at the glass/electrode interface and within the polarized glass matrix, is proposed.