We get remarkable changes in IR absorption presented in Fig. 1 already with heating to 550 °C. The part of sample doped with phosphorus becomes opalescence. We did not find procedure completely restoring sample properties
We get remarkable changes in IR absorption presented in Fig. 1 alreadywith heating to 550 °C. The part of sample doped with phosphorusbecomes opalescence. We did not find procedure completelyrestoring sample properties