Sometimes you hit the Lego Lightsaber Blade lottery and get the transparent parts with no air bubbles trapped inside. I still usually end up with some that have one or sometimes many bubbles. I found that Plastruct makes 1/8" arclyic rods that work perfectly. They are 1/8" (outside diameter) by 9" Flourescent Acrylic Rods made by Plastruct.They are bubble free. They come in Red, Blue, Clear and Green and as a bonus, they do glow under a blacklight. They are easy to cut with a fine saw, or can be scored and snapped! You can finish off the edges with fine Sandpaper. I like to round out the tips to make them more "realistic" The only downside is the Red, and Blue are less vibrant and more subtle than the actual Lego counterparts. The green is a near perfect match. I also found the 1/8" rods sometimes is a bit loose when fitted into the Hilts. a bit of white glue will hold it in for displaying or you can melt the bottom of the blades with a small flame an it will fit snuggly.
I called around to many nearby hobby and craft stores but no one seemed to carry them, I ended up buying them online. Just do web search for Plastruct 1/8" acrylic rod. You can purchase them directly from Plastruct, I believe I purchased mine from hobbylinc. They cost around $5 for a set of 7 (one color) in 9" lengths.