High index polymers

**musicvirtuoso** · 04-06-2011, 06:10 PM

Okay, so let me premise this by saying that I do not work in a surfacing lab, so my experience with this is not so extensive (so, no badgering the inquirer). What exactly is the difference between MR-7 and MR-10 plastics? Is there an advantage to using one or the other?

**musicvirtuoso** · 04-09-2011, 11:46 AM

... I hope the question wasn't too stupid for people to even comment on... I was just curious...

**uncut** · 04-09-2011, 12:15 PM

This is not a silly question, at all.....I'm not @ work right now, but if nobody answers this over the weekend, I will on Monday.:)

**optical24/7** · 04-09-2011, 12:24 PM

All I know is that there doesn't appear to be a lot of difference between the two. MR7 has a R.I. of 1.658 (MR10 is 1.661) and MR7 has a specific gravity of 1.35 (MR10 is 1.37). Both have abbe's of 32. The biggest difference is in whom uses what. (lens manufacturers)

**Darryl Meister** · 04-10-2011, 02:43 AM

MR10 offers slightly higher tensile strength and slightly greater heat resistance than MR7. MR7, on the other hand, offers slightly greater impact resistance and slightly better tintability than MR10. Both are excellent materials though. As noted earlier, the optical characteristics are very similar. MR10 has a refractive index of 1.661 and MR7 has a refractive index of 1.658 in the Helium d system. The Abbe value is 32 for both materials. MR10 is also a newer lens material, which may influence the cost in some cases.

Best regards,
Darryl