I'm sorry to hear that your pup may have eaten some glass and plastic shards.
While I understand that getting the glass and plastic shards out would be nice I do not recommend inducing vomiting in cases where dogs may have eaten sharp objects. The chances of tearing their esophagus or stomach as it contracts to force the glass out is much too high.
The good news is that he is a big fellow.
In this case we need to try and hope that we can get these shards to pass through his gastrointestinal tract safely.
To help I recommend starting with feeding him a Vaseline (or any generic petroleum jelly) sandwich. Take a slice of whole wheat bread, slather with vaseline as you would peanut butter on a slice of bread, cover with a second slice. Feed it to him bite sized piece by piece or he will make a huge vaseline mess. This adds fiber and hopefully makes the pieces slip rather than catch.
For the next few days, until the shards pass, he'll need to be fed a bland diet with lots of fiber added in small meals several times a day, 4 to 6 meals is ideal. We do this so the pieces are surrounded, the gut isn't irritated anymore by contracting on just sharp fragments.
You can either use prescription Hills i/d diet as a base or a homemade diet. You can make a homemade bland diet mix with 1/3 boiled, lean hamburger or boiled, white, skinless chicken, all fats drained of the meat, and 2/3 boiled, plain white rice. Add 2-4 tablespoons of canned pumpkin, (not pie filling, just pumpkin), to each meal for fiber whether you are feeding the i/d diet or homemade version.
You'll need to check his stools frequently for pieces in the next few days.
Signs that things aren't going well, and he needs an immediate veterinary visit, are vomiting, a tense painful belly, lack of an appetite, a fever (more than 103.5F rectally), frank blood or black tarry stools, and lethargy.
If you aren't seeing fragments in the next day or two a veterinary visit and an abdominal radiograph to see where the shards are is an option. Most glass will show up on radiographs, though not all. If in doubt at all that things aren't going well it is always best to have him checked.
Once the pieces are passed and he's feeling well then start mixing in his regular food, adding a little more regular and less bland at each meal. It should take a week to get him converted back to regular food. They should pass within the next 3-5 days.
Please let me know if you have any further questions.