Only in an emergency! (& it would have to be a serious emergency!
)
I've read articles about the designs of guitar strings. Generally it is agreed that strings are best used for the concert pitch for which they are designed (i.e. 3rd = G) but most strings can comfortably handle a whole tone above that, so D/4th would be comfortable tuned up to E but may be under stress of breaking above this.
So my suggestion would be that if it is an emergency use your spare 2nd (B) & tune it down to G, this will suffice short term until you buy a new 3rd string.
Dan
