FSC239Y5 Lecture Notes - Lecture 19: Borosilicate Glass, Sodium Carbonate, Glass Pieces
Document Summary
Centre of forensic science: chemistry section trace analysis glass (about 40-50 cases/ year) From the cfs forensic glass examination glossary: glass is a brittle, non crystalline usually transparent or tranluscent material that is formed by the melting of sand with soda ash and limestone. What"s in glass: raw material, sand (silica, soda ash. Limestone: dolomite, aluminaite, feldspar, etc, oxide supplied, sio2, na2o, cao, cao, mgo, al2o3, etc, chemical composition is the key factor controlling the physical properties of glass. Flat glass: architectural, automotive, container, miscellaneous, optical, decorative, etc. Soda-lime-silica glass: contains si, most common glass, borosilicate glass, contains 10-25% baron oxide, used in automotive headlights , laboratory and industrial glassware (pyrex) Leaded glass: contains 35-65% lead oxide, used in crystal tableware, old tv tubes. Forensic significance of glass: as trace evidence. Type of fracture/ direction of impact/ sequence of impacts.
