RAMAN STUDY OF THE CHEMICAL REACTIONS DURING THE MELTING OF A 15 Na2CO3-10 BaCO3-75 SiO2 BATCH D.M. Krol and R.K. Janssen J. Phys. Colloques, 43 C9 (1982) C9-347-C9-350 DOI: 10.1051/jphyscol:1982966