A variety of borate glass compositions are shown to be effective in inhibiting bacterial growth on their surfaces. Both Gram-negative (Escherichia coli & Salmonella typhimurium) & Gram-positive bacteria (Staphylococcus atreus) were effectively killed by lithium borate & lithium potassium borate glasses of high & low alkali contents. The surface environment was shown to become acidic for low metal contents, halting growth & alkaline for higher metal contents. The alkaline surface layer proved to be more efficient in eliminating bacteria. The more alkaline sample also appeared to act especially rapidly in preventing growth. Micro- Raman measurements were taken to characterise the surface layer responsible for the bacterial inhibition.