What colour is clearish orange vitamin C solution supposed to change to when dark blue DCPIP solution is dropped into it?

I'm doing an experiment to study the effects of heat on vitamin C content. 


I planned to titrate DCPIP (2,6-Dichlorophenolindophenol, *Tillmans'* reagent) solution into a fixed volume of vitamin C solution heated at different temperatures. 


Basically I thought, the more DCPIP I used, the higher the vitamin C content. 


I know DCPIP will turn pink when acid like Vitamin c is dropped into it, then colourless once it's oxidized. 


If my research is correct, the reverse should happen if I drop DCPIP into vitamin C; it's colourless or the colour of vitamin C, then once all the vitamin C has been oxidized the vitamin C turns blue because DCPIP is in excess.


However, when I tried it out, even in very small volumes of Vitamin C and large volumes of DCPIP, the solution doesn't change colour. Could anybody tell me the possible reason for this? 


Perhaps I have made an error or my assumption is completely wrong. Please help. 


