Patent ID: 7045475

Claim:
Glass beads having a refractive index of at least 1.59 and having the following composition as stated in weight percent: SiO 2 =55–65 R 2 O=10–20 RO=5–15 RO 2 =10–25 R 2 O 3 =0–5 Other components=0–2 wherein R 2 O is one or more alkali metal oxides; RO is selected from the group consisting of alkaline earth metal oxides, ZnO, and combinations of these; RO 2 is TiO 2 , ZrO 2 , or a combination thereof; R 2 O 3 is B 2 O 3 , Al 2 O 3 , or a combination thereof; and wherein R 2 O comprises Na 2 O in an amount equal to at least 10 wt % of the glass.