Network Structure of Borophosphate Glasses (Part 2)

Raman Spectra of Potassium Borophosphate Glasses

Abstract

Raman spectra have been measured for the potassium borophosphate glasses. The observed bands are assigned to six-membered borate rings, phosphate chain or network composed by O=PO_3/2 or KPO₃ units and six-membered borophosphate clusters incorporating [PO_4/2]⁺ or O=PO_3/2 units by taking the Raman bands characteristic of the borate and phosphate units in the literature as the reference. Crystalline BPO₄ type network is absent in the present glasses. The following four bands have been attributed to the borophosphate units; 1030cm^-1 to PO₂ with the P atom bonded to B, 720cm^-1 to the breathing vibration of six-membered B-O-P rings, 600 and 550cm^-1 to P-O-B bonds. The coexistence of the BO₃ and PO_2.5 have also been proposed.