b) 0.25 to 15% by weight, based on total solids in the composition, of a lead tellurium lithium oxide wherein the lead tellurium {TAIL ~ lithium oxide} comprises {HEAD ~ 0.1 to 5 wt %} Li2O; and 
b ) 0.25 to 15 % by weight , based on total solids in the composition , of a lead tellurium lithium oxide wherein the lead tellurium { TAIL ~ lithium oxide } comprises { HEAD ~ 0.1 to 5 wt % } Li2O ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH