X-ray absorption studies of the short-range order in lithium aluminosilicate glass-ceramics

Abstract

Measurements of the Extended X-ray Absorption Fine Structure (EXAFS) and of the X-ray Absorption Near Edge Structure (XANES) are presented as methods to determine the element specific short-range order in amorphous and crystalline materials. Changes of the short-range order of the nucleating agents in a lithium aluminosilicate glass are investigated as function of heat treatment to get information on the mechanisms of nucleation and crystallization. XANES of the Ti K-edge of the glass and of specimens of various stages of the ceramification indicates a change of the environment of Ti4+ ion from tetrahedral to octahedral coordination. The EXAFS results also show an increase of the coordination number of Ti4+ ion associated with a larger Ti-O distance during the devitrification of the glass.