A laser will have a hard time popping white balloons, clear balloons, or balloons that are the same color as the laser light. In order for the laser to pop a balloon, the light must be first absorbed by the material and allowed to heat up and fail. We see that balloon as being blue because blue light is then most promenint color of light that is relflected off of it, and the samething will happen with your laser. A blue balloon will pass and reflect a blue laser better than any other color.