Effect of Both Acid and Base Etching on Phosphate Laser Glass Surfaces

The effect of chemical etching processes on phosphate laser glass surfaces was investigated. Under different process conditions (e.g. sonication and agitation), conventionally polished and subsequently washed phosphate glass plates were treated by submerging in both HCl and KOH solution either with or without BaCl2. Subsequently, Raman spectra and X―ray photoelectron spectroscope (XPS) of the treated surfaces were measured. The precipitation of metal cations and depolymerization of the glass network structure are the two main chemical reactions in both solutions: One refers to the substitution of P―O―H for P―O―M, the other is that the Q2 tetrahedra, the basic structural unit of the original metaphosphate glass, has gradually been replaced by the Q1 or Q0 tetrahedra. Finally, the reaction models of phosphate laser glasses dissolved in both HCl and KOH solution are proposed.