Avodah Zarah 34a: The Torah testifies that a ceramic vessel absorbs the taste of the food cooked in it, and can never be kashered and cleansed from that taste.
Orach Chaim 451:26: Glass vessels, even if food was kept in them long term, or if they were used with hot food, do not require any kashering, because they do not absorb taste; it is enough to wash them. Rema: But some are strict and say that glass vessels do absorb and cannot be kashered, and this is the custom in Germany and these countries.
ע”ז לד ע”א: התורה העידה על כלי חרס שאינו יוצא מידי דופנו לעולם.
שו”ע או”ח תנ”א, כ”ו: כלי זכוכית אפי׳ מכניסן לקיום ואפילו משתמש בהם בחמין א״צ שום הכשר שאינם בולעים ובשטיפה בעלמא סגי להו: הגה ויש מחמירין ואומרים דכלי זכוכית אפילו הגעלה לא מהני להו וכן המנהג באשכנז ובמדינות אלו (סמ״ק ואגור).
A young man about 26 years old came to Rabbi Yisroel Belsky and asked, “Does Corelle absorb like glass or like ceramic?”
Rav Belsky replied, “Corelle is about 88% glass and about 12% ceramic; the company doesn’t disclose the exact composition. But the Rema says at the end of siman 451 that Ashkenazic custom is to consider glass like ceramic, which absorbs non-kosher taste and cannot be kashered. So no matter what Corelle is, you should be strict.
“But,” Rav Belsky continued, “I gather from your question that you must have looked at the Mishnah Berurah, and you saw that he says that in cases of loss one may rely on the Mechaber who says that glass doesn’t absorb taste at all. And your case is a case of loss.”
“That’s right, that was my shailah,” said the young man.
“Okay, then,” said Rav Belsky, “I’ll answer your shailah, but I have something very important to tell you. First and foremost, I want to give you a bracha that every Corelle dish that you have should be broken and smashed and end up in the garbage can! Not even one should be left over as a zeicher. And you should buy a new set, and that set should also be broken and smashed!”
The young man looked puzzled.
“Listen to me,” said Rav Belsky. “When you say this is a case of loss, you mean that your wife got into a big fight with you, because a Corelle plate somehow became treif in your home, and both of you are very angry. Because if that plate gets thrown out, the set will be incomplete. Is this true?”
“Yes,” the young man admitted.
“You want to have a family with children, who will fill the house with laughter and happiness? So I’m giving you a blessing that you should have children. And children love to break dishes. The Gemara says in Yuma 78b that it is normal for children to break dishes – that is the healthy way for them to grow, and if they don’t, it must be that their parents terrorize them too much. There is too much pressure and strictness in the home. A child growing up in such a house will be a very unhappy child, who will have problems later in life. So you want your children to break the dishes. All your dishes will eventually get broken. Throw away this dish, and when your kids break dishes, give them a kiss and tell them it’s nothing, tell your wife it’s nothing, and tell her that you’ll buy her a new set of Corelle, and another new set after that. Don’t make a problem over a dish and don’t have shailos. You should have so much happiness in your house, the kids should jump all over the place and break the furniture.”
The young man remarked, “I’m walking away from this conversation a wise person. What I’ve learned in the last couple of minutes is more valuable to me than anything I’ve ever learned before.”
Source: Audio shiur on chinuch by Rav Belsky
Read and Remember 