The deterioration behavior of protective coatings in various aqueous solution systems was investigated by scanning vibrating electrode technique (SVET). In aqueous salt solutions of potassium carbonate (K2CO3) and sodium sulfate (Na2SO4), the ability of corrosion protection was in the order epoxy (EP) > polyester (ES) > polyvinyl chloride (VC) resins; this order corresponded to that in aqueous sodium chloride (NaCl) solution as previously reported. In aqueous HCOOH solution, the current density (i) by SVET of each paint film was in the order ES<VC ; this order corresponded to those in aqueous CH3COOH and H3PO4 solutions as previously reported, and also to that in aqueous K2CO3 and Na2SO4 solutions. From the previous and present data, in various aqueous solution systems, i increased in the order 100 ppm (2.0mmol · dm-3) NaCl <0.5mmol·dm-3 Na2SO4 <0.5mmol dm-3 K2CO3<0.3mmol ·dm-3 H3PO4 <1% (0.26mol· dm-3) HCOOH. A linear correlation between current density determined by SVET and lifetime (or film resistance) determined by electrochemical impedance spectroscopy (EIS) exists in various aqueous solution systems. This linear correlation was shifted to higher current density (i) in more corrosive aqueous solutions.
Thiazolylazo nonlinear optical chromophores (NLOphores) having hydroxy groups in the molecule have been synthesized. The second-order nonlinear optical coefficients (d33) of these NLOphores doped in poly (methyl methacrylate-co-metha-crylic acid) (poly (MMA-co-MAA)) were observed to be 16 to 22 pm V-1. The temporal stability of oriented NLOphores was in the order of the hydroxy-substituted thiazolylazo derivatives : tri > di > hydroxy-free.