Sunglasses No Glare

Running with sunglasses: When running a marathon, where should I put my sunglasses when I did not need this?
I run to Singapore, where equatorial climate experiments. My marathon is 8, where usually the sun becomes sweet enough, so I'm facing a pair of sunglasses for my career. However, if the race day itself, the sun begins to occur only say, 8.30. Where I can put my sunglasses from 8 to 8.30? pull them up in my head? Or should I use during the race? Answers are greatly appreciated.
put them in a small box and attach to your material pocket or something. What I'm doing.