LASER SPECTROSCOPY AND FLUORESCENCE LINE NARROWING OF Cr3+ IN LaCaZrSiB2 O3 GLASS AND GLASS-CERAMIC A. BRUCE, J.A. CAPOBIANCO, G. CORMIER, D. KRASHKEVICH and D.J. SIMKIN J. Phys. Colloques, 48 C7 (1987) C7-459-C7-461 DOI: 10.1051/jphyscol:19877109