Metaphosphate glasses have been irradiated and dissolved in aqueous solutions, where the trapped positive and negative species, MP+ and MP-, respectively, reacted with scavengers. I-, O2, Fe(CN)e4-, Fe3+, and TMPD have been used to scavenge MP+ and MP-. From product analysis, G(MP+) = G(MP~) = 2.2 ± 0.1 was calculated. Combining this with absorbance measurements in glasses yields esoo(MP+) (the extinction coefficient of MP+ at 500 nm) = (1.92 ± 0.17) X 103 M-1 cm-1. MPreacts with aqueous O2 to produce peroxy radicals (O2or MPO2-). Whatever peroxy radicals are formed, they decay in water to produce H2O2. MPdoes not react with N2O and does not produce H2 upon reaction with alcohols in acid solutions. It is concluded that MPdoes not form eaq-or H upon its interaction with water. Pulse radiolysis experiments show that aqueous solutions of metaphosphate are relatively inert toward eaq-and OH. fe(eaq~+ MP) < 1 X 106 and A (OH + MP) < 5 X 106 M-1 sec-1.

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The yields of radiation-induced electrons and holes trapped in the glass matrix are easily determined by introducing metal ions, such as Sb, Mo, and U ions, into water-soluble NaPO3 polymer glass. Doping 1 mol % of these ions of a lower oxidation state wholly prevents the trapping of holes and results in oxidation to their higher oxidation states. A reaction in the reverse direction also occurs for the same ions of a higher oxidation state, which are converted into a lower one by reduction. This radiation-induced redox reaction has a minimum yield at a dopant composition corresponding to Sb2O4 for Sb(III)–Sb(V), Mo6O17 for Mo(V)–Mo(VI), and U3O8 for U(IV)–U(VI) redox couples. The largest effective volume among these ions for capturing the holes is for Sb(III). In a high-dose region (1020 to 1021 eV/g), the yields of the redox products of these ions increase logarithmically with the γ-dose absorbed. This makes it difficult to determine the G-value of the redox products precisely. The approximate values are in an order of magnitude of 0.1 atom per 100 eV absorbed.

The single crystal of K3P3O9 was irradiated by gamma-rays at room temperature. The pink colored crystal (absorption maximum at around 500 nm and esr spectrum with g=2.01 and a coupling constant of 36G.) was dissolved in aqueous iodide solutions and the liberated iodine was quantitatively measured. From the product analysis, the initial G values were determined as G(P4+) = G(P6+) = 0.27±0.05 at 20°C.

Much work has been carried out on the radiation chemistry of various ions using sodium metaphosphate glass (MP) as a matrix (1).Glass samples are generally prepared by , melting NaH2P04 (mp 620 °C) in platinum crucibles. The crucibles employed were made of pure platinum and supplied by Johnson Matthey Metals Ltd. Using this procedure, we observed the presence of platinum ions in the produced glass samples. A convenient analytical procedure was found to be an adaptation of the iodide spectrophotometric method for platinum (2).The tetraiodoplatinate(II) and hexaiodoplatinate(IV) systems were extensively investigated before (3, 4).The equilibria involved in the present work are:Pt(II) + 4Ptl42" Ki(1) h pti42-+ i3-5=t ptis2-+ r 2(2)t-2 EXPERIMENTAL Spectral Measurements. Ptle2was prepared by equilibration of 10-S-10-4AÍ K2PtCle with 0.05-0.5M HI over a period of 50 hr.We found two peaks, at 492 nm (e = (1.26 ± 0.03) X 104M-1 cm-1 and 343 nm (« = (1.80 ± 0.05) X 104 /-1 cm-1), and a shoulder at 443 nm (e = 0.82 ± 0.02) X 104M-1 cm-1). These results were observed in the presence of 0.5-4M MP (calculated on the basis of