The Electron Spin Resonance of γ-Irradiated Sodium Polyphosphate. I. The Glass and the Single Crystal

Under irradiation with γ-rays at room temperature, the glass of sodium polyphosphate or its single crystal doped with sodium sulfate becomes red, whereas the pure single crystal remains colorless. The glass and the doped single crystal exhibit ESR spectra which can be attributed to the hole trapped in the non-bonding orbital on the oxygen atom. The pure single crystal, of course, exhibits no ESR spectra. The determination of the degree of polymerization in the aqueous solution of the glass showed a decrease in the length of the main chain caused by the γ-ray irradiation. It may be concluded from these facts that the P–O–P bond is ruptured under the irradiation and that the effect of γ-rays on sodium polyphosphate is closely correlated with the local strain of the P–O–P bond.