ESR and optical absorption of cupric ion in borate glasses

Abstract

ESR and optical absorption of Cu 2+ were measured in xNa 2O(100− x)B 2O 3 (1 ≤ x ≤ 75), x ZnO(100− x)B 2O 3 (46 ≤ x ≤ 64) and x Pb(100−x)b 2 O 3 (20 ≤ x ≤ 75) glasses, where x is expressed in mol.%. Spin hamiltonian parameters and ligand field absorption energy changed abruptly in the regions of 15 ≤ x ≤ 23 and 37 ≤ x ≤ 55 in the soda system, while both parameters were hardly dependent upon the glass composition in zinc and lead systems. The magnitude of micro-environmental fluctuation of Cu 2+-complexes in the glasses was estimated qualitatively and correlated with the distribution of the strength of π-bonding between cupric ion and oxygen in the glass. Typical network modifiers and intermediates behaved differently, especially in the composition region of invert glass; the large deformation of the coordination sphere of Cu 2+ in lead glasses due to the stronger PbO bond resulted in the large distribution of g  . The situation was reverse in the case of soda glasses.